Department of Health and Human Services 

OFFICE OF 

INSPECTOR GENERAL 

ADVERSE EVENTS IN SKILLED 

NURSING FACILITIES: 

NATIONAL INCIDENCE AMONG 

MEDICARE BENEFICIARIES 

Daniel R. Levinson 

Inspector General 

February 2014 

OEI-06-11-00370 
 

EXECUTIVE SUMMARY: Adverse Events in Skilled Nursing Facilities: National 

Incidence Among Medicare Beneficiaries 

OEI-06-11-00370 

WHY WE DID THIS STUDY 

From 2008–2012, we conducted a series of studies about hospital adverse events, defined as harm 

resulting from medical care. This work included a Congressionally mandated study to determine a 

national incidence rate for adverse events in hospitals. As part of this work, we developed methods to 

identify adverse events, determine the extent to which events are preventable, and measure the cost of 

events to the Medicare program. This study continues that work by evaluating post-acute care provided 

in skilled nursing facilities (SNF). SNF post-acute care is intended to help beneficiaries improve health 

and functioning following a hospitalization and is second only to hospital care among inpatient costs to 

Medicare. Although various health care stakeholders have in recent years paid substantial attention to 

patient safety in hospitals, less is known about resident safety in SNFs. 

HOW WE DID THIS STUDY 

This study estimates the national incidence rate, preventability, and cost of adverse events in SNFs by 

using a two-stage medical record review to identify events for a sample of 653 Medicare beneficiaries 

discharged from hospitals to SNFs for post-acute care. Sample beneficiaries had SNF stays of 35 days 

or less. 

WHAT WE FOUND 

An estimated 22 percent of Medicare beneficiaries experienced adverse events during their SNF stays. 

An additional 11 percent of Medicare beneficiaries experienced temporary harm events during their 

SNF stays. Physician reviewers determined that 59 percent of these adverse events and temporary 

harm events were clearly or likely preventable. They attributed much of the preventable harm to 

substandard treatment, inadequate resident monitoring, and failure or delay of necessary care. Over 

half of the residents who experienced harm returned to a hospital for treatment, with an estimated cost 

to Medicare of $208 million in August 2011. This equates to $2.8 billion spent on hospital treatment 

for harm caused in SNFs in FY 2011. 

WHAT WE RECOMMEND 

Because many of the events that we identified were preventable, our study confirms the need and 

opportunity for SNFs to significantly reduce the incidence of resident harm events. Therefore, we 

recommend that the Agency for Healthcare Research and Quality (AHRQ) and the Centers for 

Medicare & Medicaid Services (CMS) raise awareness of nursing home safety and seek to reduce 

resident harm through methods used to promote hospital safety efforts. This would include 

collaborating to create and promote a list of potential nursing home events—including events we found 

that are not commonly associated with SNF care—to help nursing home staff better recognize harm. 

CMS should also instruct State agency surveyors to review nursing home practices for identifying and 

reducing adverse events. AHRQ and CMS concurred with our recommendations. 
 

TABLE OF CONTENTS 

Objectives ....................................................................................................1 

Background..................................................................................................1 

Methodology..............................................................................................12 

Findings......................................................................................................17 

An estimated 22 percent of Medicare SNF residents 

experienced adverse events during their SNF stays .......................17 

An additional 11 percent of Medicare SNF residents 

experienced events during their SNF stays that resulted in 

temporary harm ..............................................................................20 

Physician reviewers determined that 59 percent of adverse 

events and temporary harm events were clearly or likely 

preventable ....................................................................................22 

Over half of the residents who experienced harm went to a 

hospital for treatment, with an estimated cost to Medicare of 

$208 million in August 2011 .........................................................25 

Conclusion and Recommendations ............................................................27 

Agency Comments and Office of Inspector General Response.....30 

Appendixes ................................................................................................32 

A: Glossary of Select Medical Terms ...........................................32 

B: Methodology for Identifying Events and Determining 

Preventability .................................................................................34 

C: Development and Description of the SNF Trigger Tool ..........40 

D: Estimates, Confidence Intervals, and Key Statistics ................42 

E: Rates of Adverse Events and Temporary Harm Events in 

SNFs by Resident Days and SNF Admissions ...............................47 

F: Adverse Events and Temporary Harm Events ..........................48 

G: Agency Comments ...................................................................59 

Acknowledgments......................................................................................65 
 

 

 

OBJECTIVES 

1.	 To estimate the national incidence of adverse and temporary harm 

events for Medicare beneficiaries admitted to skilled nursing facility 

(SNF) for post-acute care. 

2.	 To assess the extent to which adverse and temporary harm events were 

preventable and identify contributing factors. 

3.	 To estimate the costs associated with adverse and temporary harm 

events to the Medicare program. 

BACKGROUND 

The Office of Inspector General (OIG) conducted a series of studies about 

adverse events in hospitals from 2008–2012.1 This work included a 

Congressionally mandated study of adverse event incidence within 

hospitals.2, 3 OIG found that 27 percent of hospitalized Medicare 

beneficiaries experienced adverse and temporary harm events, nearly half 

of the events were preventable, and care associated with events cost the 

Medicare program an estimated $4.4 billion a year. OIG has identified a 

number of problems with the quality of care provided in nursing homes, 

including SNFs. These problems include inadequate discharge planning 

and lack of compliance with CMS standards regarding the use of atypical 

antipsychotic drugs.4, 5 These problems pose risks to individuals and 

increase Medicare costs in the form of hospitalizations. 

Medicare expenditures for SNF care have more than doubled in the last 

decade. Medicare paid $12 billion for SNF care in 2000 and $26 billion in 

2010.6, 7 In fiscal year (FY) 2011, Medicare paid $28.4 billion for SNF 

1 OIG released 11 reports regarding adverse events in hospitals during 2008-2012, 

including reports about the incidence of adverse events, methods for identifying adverse 

events, State reporting systems, and public disclosure of event information. All reports 

are available at http://oig.hhs.gov/reports-and-publications/oei/a.asp#adverse_care. 2

 Tax Relief and Health Care Act of 2006, P.L. 109-432 § 203. 

3

 OIG, Adverse Events in Hospitals: National Incidence Among Medicare Beneficiaries, 

OEI-06-09-00090, November 2010. 

4

 OIG, Skilled Nursing Facilities Often Fail To Meet Care Planning and Discharge 

Planning Requirements, OEI-02-09-00201, February 2013. 5

 OIG, Nursing Facility Assessments and Care Plans for Residents Receiving Atypical 

Antipsychotic Drugs, OEI-070800151, July 2012. 6

 U.S. Department of Health and Human Services (HHS), Office of the Actuary, National 

Health Statistics Group, SNF Utilization Chart, 2010, p. 50. 7

 Medicare Payment Advisory Committee (MedPAC), Skilled Nursing Facility Services 

Payment System, updated October 2011, p. 1. 

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services provided to 1.8 million beneficiaries.8 Post-acute SNF stays— 

which we define for the purposes of this study as SNF stays that began 

within 1 day of discharge from a hospital and lasted 35 days or less— 

constitute 70 percent of all Medicare beneficiary stays in SNFs.9 

Adverse Events 

The term “adverse event” describes harm to a patient or resident as a result 

of medical care.10 An adverse event indicates harm to the patient as a result 

of medical care, including the failure to provide needed care. Adverse 

events include medical errors but they may also include more general 

substandard care that results in patient or resident harm, such as infections 

caused by the use of contaminated equipment. However, adverse events do 

not always involve errors, negligence, or poor quality of care and are not 

always preventable.11,12 

Post-Acute Care in SNFs 

The Social Security Act (SSA) §1819(a) defines a “SNF” as a facility 

engaged primarily in providing skilled nursing care and rehabilitation 

services for residents who require such care because of injury, disability, 

or illness. Although the term “SNF” refers to a provider that meets the 

Medicare Part A coverage requirements described above, 90 percent of 

SNFs are dually certified as both SNFs and nursing homes (i.e., long-term 

care providers).13 In 2011, about 20 percent of all hospitalized Medicare 

beneficiaries went to one of the 15,207 SNFs for post-acute care following 

their hospital stays.14 Medicare Part A pays for up to 100 days of care in 

SNFs per benefit period.15, 16 Medicare beneficiaries are eligible for SNF 

stays following a hospital stay of at least 3 days and when a medical 

8

 Centers for Medicare & Medicaid Services (CMS), 2011 CMS Statistics, Tables III.6 

and IV.6a. Accessed at www.cms.gov/ResearchGenInfo/02_CMSStatistics.asp on 

April 9, 2012. 

9

 OIG analysis of 2010 Medicare SNF claims, Standard Analytical File (SAF). 10 See Appendix A for a definition of “adverse events” as well as a list of select clinical 

terms and conditions.
 11 R.M. Wachter, Understanding Patient Safety, McGraw-Hill, 2008, p. 17. 12 OIG, Adverse Events in Hospitals: National Incidence Among Medicare Beneficiaries, 

OEI-06-09-00090, November 2010. 

13 MedPAC, Report to the Congress: Medicare Payment Policy, Skilled Nursing Facility 

Services, March 2013, p. 161. 14 Ibid. 

15 A “benefit period” is a period of consecutive days during which medical benefits for 

covered services, with certain specified maximum limitations, are available to the 

beneficiary. CMS, Medicare Benefit Policy Manual: Duration of Covered Inpatient
 

Services, Chapter 3.
 16 CMS, Medicare Benefit Policy Manual: Coverage of Extended Care (SNF) Services 

Under Hospital Insurance, Chapter 8. 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 2 
 

 

 

professional verifies the need for nursing care and rehabilitation related to 

the hospitalization.17 

In 2010, MedPAC described Medicare beneficiaries in SNFs as more 

likely than other Medicare beneficiaries to report poor health status, have 

multiple limitations in their activities of daily living, live in an institution, 

and be disabled.18 Examples of SNF residents include those recovering 

from surgical procedures performed in hospitals (e.g., hip or knee 

replacements) or recovering from acute medical conditions (e.g., stroke, 

pneumonia).19 Examples of care provided to SNF residents include the 

development, management, and evaluation of a resident care plan; 

physical therapy; administration of intravenous feedings; medication 

management; and wound care. 

Medicare Payment to SNFs. Medicare payment to SNFs is determined by 

rate groups based on the level of care provided and is adjusted for 

geographic and resident population differences. Each of these 66 rate 

groups—referred to as “resource utilization groups,” or “RUGs”—in 

8 categories have weights for nursing and therapy care that are applied to 

the base rates.20 Assignment to a rate group is based on the number of 

minutes of therapy that the resident requires, the need for certain services 

(such as respiratory therapy), the presence of certain conditions (such as 

dehydration), and an index based on the ability of the resident to 

independently perform four activities of daily living (i.e., eating, toileting, 

bed mobility, and transferring).21 

Federal Oversight of Nursing Homes 

CMS oversees nursing home compliance with Federal standards through 

State survey agencies, which monitor SNFs and enforce penalties for 

substandard quality of care.22, 23 Surveys may include medical record 

review and audits of resident assessments or plans of care.24 CMS enters 

into agreements with State survey agencies to conduct onsite surveys of 

17 Ibid. 

18 MedPAC, op. cit., p. 162-163. 

19 MedPAC, op. cit., p. 161. 20 CMS, Resident Assessment Instrument (RAI) Version 3.0 Manual (v. 1.07), ch. 6, § 6.3. 21 Ibid, ch. 6, § 6.6.
 22 42 CFR Part 488, Subparts E and F. 

23 CMS, State Operations Manual, Appendix PP, Guidance to Surveyors for Long Term 

Care Facilities, Tag F309.
 24 42 CFR §§ 488.305(a) and 488.310(b).
 

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each nursing home to certify compliance with Federal requirements.25 

When surveyors identify noncompliance with Federal requirements, CMS 

requires nursing homes to submit plans of correction and to correct the 

problems. If nursing homes do not correct the problems, CMS may take 

enforcement actions, including imposing civil monetary penalties and 

denying payment for new admissions of Medicare residents.26 

CMS requirements regarding resident safety in nursing homes include 

both broad, facility-wide mandates (such as staff training) and 

requirements specific to certain practices (such as treatment of pressure 

ulcers). To establish and oversee quality and safety-related practices, 

CMS requires that nursing homes establish and maintain a Quality 

Assurance and Assessment (QAA) committee composed of a physician 

designated by the facility, director of nursing, and other staff members as 

determined by the facility.27 Tasks of the QAA include identifying and 

addressing quality and safety problems. To evaluate nursing home quality 

and safety practices, CMS instructs surveyors to review QAA committee 

activities and interview committee members as a part of onsite reviews.28 

Noncompliance with the QAA requirements can result in surveyors’ citing 

a deficiency specific to the QAA process.29 

Additionally, CMS requires that Medicare- and Medicaid-certified nursing 

homes report alleged instances of mistreatment, neglect, or abuse to State 

survey agencies.30 These instances are to include injuries of unknown 

source as well as misappropriation of resident property. When allegations 

of such instances are made, the nursing homes must take measures to 

prevent further potential abuse, investigate the allegations, and establish a 

corrective action plan if warranted.31 Federal regulation defines abuse as 

“willful infliction of injury” and neglect as “failure to provide goods and 

services necessary to avoid harm.”32 Noncompliance with the reporting 

25 42 CFR § 488.10 and CMS, Survey and Certification: General Information, April, 11, 

2013. Accessed at http://www.cms.gov/Medicare/Provider-Enrollment-andCertification/SurveyCertificationGenInfo/index.html?redirect=/surveycertificationgeninf
 

o/ on May 15, 2013. 

26 42 CFR §§ 488.402(d), 488.408, and 488.417. 27 42 CFR §§ 483.75(o).
 28 CMS, State Operations Manual, Appendix PP, Guidance to Surveyors for Long Term
 

Care Facilities, Tag F520. 

29 Ibid. 

30 42 CFR §§ 483.13(c)(2).
 31 42 CFR §§ 483.13(c)(3) and (4).
 32 42 CFR §§ 488.301.
 

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requirements results in a deficiency citation specific to the reporting 

process.33 

Nursing Home Quality Measures. Medicare- and Medicaid-certified 

nursing homes routinely collect resident assessment data at specific 

intervals during a nursing home stay and maintain the assessment results 

in the Minimum Data Set (MDS).34 CMS converts portions of the MDS 

data into 18 quality measures (QMs), which indicate how well nursing 

homes care for residents.35 Examples of QMs include the percentage of 

residents who develop pressure ulcers, the percentage who develop urinary 

tract infections, and the percentage who experience falls with injury.36 

CMS provides QMs to SNFs for use in quality improvement efforts. 

CMS publicly reports nursing home QMs through the Five-Star Quality 

Rating System and Nursing Home Compare. CMS gives each Medicareand Medicaid-certified nursing home an overall rating between one and 

five stars. A rating of one star indicates that a nursing home is “much 

below average” in terms of quality, and a rating of five stars indicates that 

a nursing home is “much above average.”37 CMS bases the overall 

ratings on the nursing homes’ performance in three areas: performance on 

inspection surveys (survey metric), QMs (quality metric), and staffing 

(staffing metric). 

Adverse Event Lists and Reporting. To date, there is no Federal 

requirement that SNFs report adverse events beyond the requirements to 

report instances of mistreatment, neglect or abuse and the discrete 

potential events described in the QMs (e.g., pressure ulcers, falls). 

Additionally, there are no Federal standards that require States to operate 

adverse event reporting systems. To help define potential events for 

reporting, the National Quality Forum (NQF) issued guidance in 2011 

expanding its list of hospital Serious Reportable Events (SRE) to SNFs 

33 CMS, State Operations Manual, Appendix PP, Guidance to Surveyors for Long Term 

Care Facilities, Tags F223-226. 

34 CMS, RAI Version 3.0 Manual (v. 1.07), ch. 1, § 1.2, and ch. 2, § 2.6. 35 RTI [Research Triangle Institute] International, Nursing Home MDS 3.0 Quality 

Measures: Final Analytic Report (Sept. 2012), §§ 1.1 and 1.2. 36RTI, MDS 3.0 Quality Measures User’s Manual (v. 6.0). Accessed at 

http://www.cms.gov/Medicare/Quality-Initiatives-Patient-AssessmentInstruments/NursingHomeQualityInits/Downloads/MDS-30-QM-Users-Manual-V60.pdf 

on February 19, 2013. 

37 CMS, Consumer Fact Sheet, December 2008. Accessed at 

http://www.cms.gov/Medicare/Provider-Enrollment-andCertification/CertificationandComplianc/Downloads/consumerfactsheet.pdf on October 

4, 2013. 

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and other health care settings.38 The NQF SRE list identifies adverse 

events that are “serious, largely preventable, and of concern to both the 

public and health care providers.”39 The 2011 updated SRE list includes 

24 events applicable to SNF care. These 24 events largely represent only 

the most egregious potential events such as a patient death or serious 

injury associated with the use of contaminated drugs or devices. 

Resident Safety in Nursing Homes 

Previous studies of adverse events in nursing homes have focused largely 

on medication-related adverse events—which are a subset of all adverse 

events—among the entire nursing home population. A 2006 review of 

seven studies measuring the incidence of medication-related adverse 

events in nursing homes revealed that such events are common and that as 

many as half of the events could have been prevented.40 

Research also indicates that patient and resident transfers between 

hospitals and nursing homes can pose problems for medically fragile 

individuals.41 Many transitions from hospitals to post-acute care occur in a 

hurried manner and have limited prior planning, occur during nights and 

on weekends when nursing homes may have fewer and less experienced 

staff, involve clinicians who may not have a relationship with the 

residents, and happen too quickly for nursing home staff to respond well 

and in a timely manner.42 Similarly, hospitalizations of nursing home 

residents increase the risk that residents will experience harm and other 

negative care outcomes.43, 44 The impact on residents during 

hospitalizations can include disruption of their care plans and greater 

38 The NQF is a consensus-building organization focused on health care quality and funded in 

part by grants from HHS. “NQF Mandate and Call to Action,” About NQF, updated January 

2012. Accessed at http://www.qualityforum.org/About_NQF/About_NQF.aspx on March 23, 

2012. 

39 NQF, “National Voluntary Consensus Standards for Serious Reportable Events in 

Healthcare,” Press Release, August 2011.
 40 S.M. Handler, “Epidemiology of Medication-Related Adverse Events in Nursing 

Homes,” The American Journal of Geriatric Pharmacotherapy, 4, 3, 2006, pp. 264-272. 41 Congressional Research Service, “Medicare Hospital Readmissions: Issues, Policy 

Options and PPACA,” Fact Sheet, September 21, 2010.
 42 E. Coleman and R.A. Berenson, “Lost in Transition: Challenges and Opportunities for 

Improving the Quality of Transitional Care,” American College of Physicians, 141, 7,
 

2004, p. 533. 

43 Assistant Secretary for Planning and Evaluation (ASPE), Hospitalizations of Nursing 

Home Residents: Background and Options, June 2011, p. 1.
 44 J.G. Ouslander, “Reducing Potentially Avoidable Hospitalizations of Nursing Home
 

Residents: Results of a Pilot Quality Improvement Project,” Journal of the American 

Medical Directors Association, 10, 9, 2009, p. 645. 

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vulnerability for disorientation, stress, and adverse events.45 

Hospitalization rates are seen as a measure of nursing home quality and 

safety and have received attention from OIG and other stakeholders.46, 47 

Federal Efforts To Improve the Quality of Post-Acute Care 

In addition to CMS, other Federal agencies share responsibility for ensuring 

health care quality and safety in nursing homes. For example, the Agency 

for Healthcare Research and Quality (AHRQ) in HHS leads efforts related to 

research and learning. The Center for Quality Improvement and Patient 

Safety (CQuIPS) within AHRQ provides national leadership in improving 

health care safety. CQuIPS objectives are to develop a solid evidence base, 

design useful tools, and disseminate information for implementation to all 

health care facilities.48 AHRQ is also required by statute to produce an 

annual report to Congress about health care quality.49 

Patient Safety Organizations. AHRQ maintains responsibility for 

implementing and overseeing the certification process for Patient Safety 

Organizations (PSO) created by the Patient Safety and Quality 

Improvement Act of 2005 (PSQIA).50 PSOs are intended to receive 

adverse event reports from health care facilities and then forward the 

information to a national database from which CQuIPS will analyze 

aggregated data. PSQIA also provides Federal privilege and 

confidentiality protections for information reported to PSOs.51 These 

protections prohibit other entities from accessing adverse event reports, 

including State survey agencies, with providers facing possible penalties 

enforced by the HHS Office of Civil Rights. Officials at AHRQ and CMS 

indicated in interviews with OIG staff that the PSQIA confidentiality 

provision may be in conflict with CMS compliance requirements that 

allow surveyors access to facility QAA actions and reports. 

To facilitate reporting, AHRQ developed a set of event definitions and 

reporting tools—the Common Formats—which PSOs can choose to use 

45 E. Hutt, “Precipitants of Emergency Room Visits and Acute Hospitalization in 

Short-Stay Medicare Nursing Home Residents,” Journal of the American Geriatrics 

Society, 50, 2, 2002, 223–224. 46 OIG, Medicare Nursing Home Resident Hospitalization Rates Merit Additional 

Monitoring, OEI-06-11-00040, November 2013. 47 ASPE, op. cit., pp. 8–12. 

48 AHRQ, Advancing Patient Safety: A Decade of Evidence, Design, and
 

Implementation, AHRQ Publication No. 09(10)-0084, November 2009. 

49 Public Health Service Act (PHSA), § 913, 42 U.S.C. § 299b-2. 50 The Secretary of HHS delegated authority to AHRQ to certify entities as PSOs, as well 

as to fulfill other requirements of the PSQIA. P.L. 109-41 § 2, PHSA, § 924, 42 U.S.C. §
 

299b-24; 73 Fed. Reg. 70732 (Nov. 21, 2008). 

51 P.L. 109-41 § 2, PHSA, § 924, 42 U.S.C. § 299b-24.
 

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and which contain data elements that AHRQ determined are important for 

a complete and useful adverse event report.52 AHRQ designed the 

Common Formats for both the hospital and SNF settings.53 The Patient 

Protection and Affordable Care Act (ACA) provides that, by January 1, 

2015, health plans that participate in insurance exchanges may not 

contract with a hospital of 50 beds or more unless that hospital reports 

patient safety data to a PSO.54 Currently, no such requirement exists for 

SNFs. 

The ACA also mandated HHS to establish a national strategy for quality 

improvement in health care,55 including patient and resident safety,56 and 

increased funding to AHRQ for research grants to explore best practices.57 

As part of this strategy, CMS introduced in 2011 its Partnership for 

Patients, a public/private collaboration to improve health care quality and 

safety, specifically including transitions from acute to post-acute care.58 

HHS also developed the Measure Applications Partnership (MAP), a 

public/private partnership facilitated by NQF and designed to provide 

CMS and other agencies within HHS with input regarding health care 

performance measurement, in order to satisfy a mandate in the ACA to 

seek multi-stakeholder group input.59 MAP recently released a draft set of 

core measure concepts to use in assessing post-acute care by facilities such 

as SNFs, identifying both care coordination and safety as two of six 

high-leverage priority areas.60 

The ACA also requires nursing homes to develop and operate Quality 

Assurance and Performance Improvement (QAPI) programs.61 In June 

2013, CMS released guidance to nursing homes regarding developing and 

52 AHRQ, Common Formats for Patient Safety Data Collection and Event Reporting, 

Notice of Availability: Common Formats Version 1.0, September 2, 2009.
 53 AHRQ, Users Guide: AHRQ Common Formats for Skilled Nursing Facilities Version
 

0.1 Beta Release, February 2011.
 54 P.L. 111-148 § 1311, (h)(1)(A), i-ii. 55 P.L. 111-148 § 3011, PHSA, § 399HH, 42 U.S.C. § 280j. 56 ACA, § 3011, PHSA, § 399HH(a)(2)(B)(vii), 42 U.S.C. § 280j(a)(2)(B)(vii). 57 ACA, § 3501, PHSA, §§ 933 and 934, 42 U.S.C. §§ 299b-33 and 299b-34.
 58 CMS, Partnership for Patients: A Common Commitment, April 2011. Accessed at 

http://www.healthcare.gov/compare/partnership-for-patients/about/index.html on 

March 7, 2012. 

59 ACA § 3014. 

60 NQF, Input on Measures Under Consideration by HHS for 2012 Rulemaking: Final 

Report, Measure Applications Partnership, February 2012, pp. 99-100.
 61 ACA, 6102, Social Security Act, § 1128I(c), 42 U.S.C. § 1320a-7j(c). 

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maintaining QAPI programs.62 This guidance states that QAPI programs 

are to serve as comprehensive plans to both improve routine facility 

practices and to conduct periodic, targeted performance improvement 

projects. It further states that facilities are to continue working within the 

prior Federal requirements, relying on QAA committees to implement and 

oversee QAPI activities.63 CMS provides QAPI tools for identifying and 

addressing quality and safety programs, such as guidance for developing a 

facility mission statement and establishing safety goals.64 

CMS, in its 2012 Nursing Home Action Plan, described several initiatives 

intended to improve resident safety and quality in nursing homes.65 These 

initiatives involve many of CMS’ nursing home oversight and payment 

tools. Action Plan initiatives include multiple refinements to the existing 

survey and certification process, improvements in data reported through 

the Five-Star Quality Rating System, demonstration projects designed to 

test the effect of payment incentives on nursing home performance and 

quality, and plans to collaborate with Quality Improvement Organizations 

and State survey agencies. 

Measuring Health Care Safety 

Research and policy to improve health care safety and reduce adverse 

events often focus on identifying systemic problems that lead to harm and 

avoid labeling the event as an outcome of negligence or poor quality. As 

part of this effort to identify problems, researchers and health care entities 

may adopt different standards for distinguishing between degrees of harm 

in defining what constitutes an adverse event. Thus, entities tracking 

events may find different results depending on the tools used to identify 

and classify events. For example, the National Coordinating Council for 

Medication Errors Reporting and Prevention (NCC MERP) Index can be 

used to classify adverse events by level of harm. The NCC MERP Index 

was initially developed to categorize the effect of medication errors. The 

index includes categories for circumstances that presented a risk but did 

62 CMS, QAPI at a Glance: A Step by Step Guide to Implementing QAPI in Your Nursing
 

Home. Accessed at http://www.cms.gov/Medicare/Provider-Enrollment-andCertification/QAPI/Downloads/QAPIAtaGlance.pdf on October 2, 2013. 63 Ibid. 

64 CMS, Guide for Development Purpose, Guiding Principles, and Scope for QAPI,
 

June 7, 2013. Accessed at http://www.cms.gov/Medicare/Provider-Enrollment-andCertification/QAPI/Downloads/QAPIPurpose.pdf on September 5, 2013.
 65 CMS, 2012 Nursing Home Action Plan, 2012. 

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not cause harm (“near misses”) and those that did cause harm.66 

Table 1 shows the NCC MERP Index for Categorizing Errors. 

Table 1: The NCC MERP Index for Categorizing Errors 

Level Description Event 

A Circumstances or events occurred that had the capacity to cause error. 

Harm does not 

reach patient 

or resident 

B Error occurred but did not reach the patient or resident. 

C Error occurred that reached the patient or resident but did not cause 

patient or resident harm. 

D Error occurred that reached the patient or resident and required monitoring 

to preclude harm or confirm that it caused no harm. 

E Error occurred that may have contributed to or resulted in temporary harm 

and required intervention. 

Harm reaches 

patient or 

resident 

F Error occurred that may have contributed to or resulted in harm and 

required an initial or prolonged facility stay. 

G Error occurred that contributed to or resulted in permanent patient or 

resident harm. 

H Error occurred that required intervention to sustain the patient or resident’s 

life. 

I Error occurred that may have contributed to or resulted in patient or 

resident death. 

Source: NCC MERP Index for Categorizing Errors, Medication Errors Council Revises and Expands Index for 

Categorizing Errors: Definitions of Medication Errors Broadened, Press Release, June 12, 2001. 

Researchers have also used the NCC MERP index for measuring and 

distinguishing other types of adverse events. The Institute for Healthcare 

Improvement (IHI), a nonprofit organization that advises health care 

providers regarding health care quality, uses a modified version of the 

NCC MERP index to measure the degree of harm, regardless of whether 

the harm was the result of error.67 

Identifying Adverse Events. Retrospective medical record review is often 

considered the most definitive method for detecting adverse events, 

because it can provide detail about both the adverse event and the 

circumstances, such as the patient’s or resident’s condition prior to and 

following the event.68 Research indicates that identifying adverse events 

retrospectively is a complex and difficult task, requiring extensive clinical 

66 AHRQ designed an alternative harm scale for use with the Common Formats. 

According to AHRQ, the AHRQ Harm Scale differs from the NCC MERP harm scale in 

that it is intended to measure the harm experienced by the beneficiary after the harm is 

ameliorated. AHRQ, Users Guide: Version 1.2 AHRQ Common Formats for Patient 

Safety Organizations, 2013. 67 F.A. Griffin and R.K. Resar, IHI Global Trigger Tool for Measuring Adverse Events, 

Institute for Healthcare Improvement Innovation Series, 2009, pp. 4–5. 

68 E.J. Thomas, D.M. Studdert, and T.A. Brennan, “The Reliability of Medical Record 

Review for Estimating Adverse Event Rates,” Annals of Internal Medicine, 136, 11, 

2002, pp. 812–816. 

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knowledge, adequate documentation, and subjective judgment on the part 

of the researcher.69 

Medical record reviews can be costly, requiring hospitals to make records 

available and substantial effort by physicians or other clinicians to review 

them. To limit physician medical record reviews to identify adverse events, 

cases can be screened to identify potential events using other methods, such 

as nurse reviews of medical records and analysis of Medicare hospitalization 

claims. One such method, the IHI’s Global Trigger Tool (GTT), uses a 

review of hospital inpatient medical records to identify “triggers” that could 

signal patient harm and indicate potential adverse events. A trigger could be 

a description of the harm or a reference that indicates potential harm, such as 

a return to surgery. The IHI GTT review is designed to be completed by 

nurse reviewers with the results then confirmed or refuted by a physician. 

Another example of a trigger tool is the Nursing Home Adverse Drug Event 

Trigger Tool.70 Unlike the IHI GTT, which focuses on all aspects of patient 

care in the hospital setting (e.g., medication, surgery, patient care), the 

Nursing Home Adverse Drug Event Trigger Tool is focused on medicationrelated adverse events in the nursing home or other long-term care settings. 

Determining Preventability. To provide additional context regarding adverse 

events, researchers have assessed whether events were preventable and 

described the factors contributing to the events. In a 2010 OIG report about 

adverse events in hospitals, physician reviewers determined that 44 percent 

of events were preventable.71 A 2008 review of eight academic studies found 

a similar result, with an average of 44 percent of events judged preventable.72 

A 2010 study that examined the incidence of adverse events in 10 North 

Carolina hospitals described 63 percent of identified events as preventable.73 

Assessing preventability can provide greater understanding of the causes of 

events, which can be used to develop actionable solutions to the systemic 

problems that lead to events. 

69 E.J. Thomas and L.A. Peterson, “Measuring Errors and Adverse Events in Health 

Care,” Journal of General Internal Medicine, 18, 1, 2003, pp. 61–67. 70 S.M. Handler, “Detecting Adverse Drug Events Using a Nursing Home Specific 

Trigger Tool,” Annals of Longterm Care, 18, 5, 2010, pp. 17-22. 71 OIG, Adverse Events in Hospitals: National Incidence Among Medicare Beneficiaries, 

OEI-06-09-00090, November 2010, p. 24. 

72 E.N. De Vries, “The Incidence and Nature of Hospital Adverse Events: A Systematic 

Review,” British Medical Journal – Quality and Safety in Health Care, 17, 3, 2008: pp. 

216–23.
 73 C.P. Landrigan, “Temporal trends in rates of patient harm resulting from medical care,” 

New England Journal of Medicine, 363, 22, 2010: 2124–34. 

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METHODOLOGY 

This report estimates the national incidence of adverse events that occurred 

in SNFs using a representative sample of Medicare SNF residents. Our 

study population includes all Medicare beneficiaries who had Medicare-paid 

SNF stays that met each of the following criteria: 

	 began within 1 day of a beneficiary’s discharge from a hospital, 

	 had a length of stay of 35 days or less (rather than the maximum 

100 days allowed by Medicare),74 and 

	 ended in August 2011. 

We included in the estimated national incidence rates all SNF resident harm 

events that occurred during the SNF stays, regardless of whether they were 

preventable. All SNF harm described in this report is attributable to the care 

provided in the SNF. Additionally, this report provides a physician 

assessment of the extent to which the identified events were preventable and 

an analysis of billing data to estimate the cost to the Medicare program for 

inpatient hospital stays and emergency room visits resulting from 

preventable and not preventable adverse events. This study largely follows 

the methodology used by OIG in the November 2010 report, which 

estimated the national incidence rate, preventability, and cost of adverse 

events in hospitals.75 

Sample Selection and Profile 

Using Medicare claims data from the National Claims History (NCH) file, 

we selected a simple random sample of 655 Medicare beneficiaries out of 

the 100,771 beneficiaries who had SNF stays that met our 3 sample 

criteria. We excluded 2 beneficiaries because the SNFs they resided in 

were under OIG investigation, which resulted in a review of 653 

beneficiaries’ SNF stays. Thirty-seven sample beneficiaries had more than 

1 SNF stay during August (35 had 2 stays and 2 had 3 stays). Combined, 

reviewed sample beneficiaries had 692 SNF stays that ended in August 

2011; the length of stay averaged 15.5 days. 

The majority (70 percent) of sample beneficiaries entered SNFs following 

hospital stays described by CMS as medical, or nonsurgical, stays. The 

most frequent medical conditions treated in these stays were septicemia 

74 In consultation with CMS, physician reviewers and geriatrician consultants, we limited 

our study population to only those stays that were 35 days or less because it allowed for 

measurement of harm in the post-acute care period. Additionally, stays that ended on the 

35th day or earlier constituted the majority—approximately 70 percent—of SNF stays in 

FY 2011. 

75 OIG, op. cit., pp. 8-11. 

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and urinary tract infections.76 The remaining 30 percent of beneficiaries 

entered SNFs following surgical hospital stays (most often for hip or knee 

joint replacements). 

Data Collection 

We requested complete medical records for the sampled beneficiaries’ 

SNF stays. We received 100 percent of the SNF records we requested.77 

As part of this request, we asked the SNFs to provide the discharge 

summaries and other key medical record documents from the hospital 

stays that preceded the post-acute stays. In cases when the SNFs were not 

able to provide the hospital records, we requested the records directly from 

the hospitals. We also requested discharge summaries and other key 

medical record documents for any hospital stay that occurred during the 

SNF stay or within 14 days of a beneficiary’s discharge from the SNF stay. 

In addition to collecting the medical record documentation, we collected 

billing data for the SNF stays and any associated hospital stays. We 

collected MDS assessment data associated with the sampled beneficiaries’ 

Part A SNF stays. We collected hospital inpatient and outpatient claim data 

associated with sample beneficiaries’ qualifying inpatient stays—as well as 

for any subsequent inpatient or emergency room visits—from the National 

Claims History file. 

Identification of Adverse and Temporary Harm Events. We conducted a twostage medical record review to identify adverse and temporary harm events.78 

The first stage was a screening process designed to identify sample 

beneficiaries who may have experienced an adverse or temporary harm 

event during their stay(s). We asked one nurse practitioner and four nurses 

(referred to as “screeners”) with IHI GTT or SNF experience to review the 

medical records and administrative data associated with the sample 

beneficiaries’ SNF stays and hospital stays. They reviewed the medical 

records and administrative data of the hospital stays for evidence of harm 

that occurred during the SNF stays. They used the OIG-developed SNF 

trigger tool to facilitate and standardize their individual reviews of the SNF 

records.79 The contracted screeners reviewed the records independently and 

each record was reviewed by one screener. Prior to beginning their reviews, 

76 Source: OIG analysis of SNF stays for 653 Medicare beneficiaries discharged in 

August 2011. 

77 We did not request records for the two stays that occurred in SNFs under OIG 

investigation.
 78 See Appendix B for an expanded description of the methodology used to identify 

adverse and temporary harm events. 

79 See Appendix C for description of the development process and a list of SNF Trigger 

Tool triggers. 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 13 
 

we provided training to all screeners on the use of the SNF Trigger Tool. 

The screeners “flagged” the records of 262 beneficiaries for the second stage 

of the review. In addition, we randomly selected 100 beneficiaries from 391 

beneficiaries who were not flagged during the screener review to determine 

a screener false-negative rate (i.e., the rate at which the screeners incorrectly 

determined that a beneficiary did not experience an adverse or temporary 

harm event). See Appendix B for a detailed description of these additional 

reviews. 

The second stage of the medical record review consisted of reviews by five 

contracted physicians of the medical records of the 262 beneficiaries flagged 

by the screening process and the records of the 100 beneficiaries selected for 

the screener false-negative rate review. The physicians reviewed the records 

independently and each record was reviewed by one physician reviewer. To 

describe the harm caused by the events, the reviewers used a modified 

version of the NCC MERP harm scale: 

	 F level—Harm occurred that prolonged the SNF stay or led to a 

transfer to a different SNF or other post-acute facility and/or 

hospitalization (i.e., admission to a hospital observation unit, 

emergency department, or inpatient care). 

	 G level—Harm occurred that contributed to or resulted in permanent 

resident harm. 

	 H level—Harm occurred that required intervention to sustain the 

resident’s life. 

	 I Level—Harm occurred that may have contributed to or resulted in 

resident death. 

The physician panel included four physicians who participated in the 

2011 OIG study of hospital events (specialists in cardiology, infectious 

disease, internal medicine, and orthopedics) and one geriatrician with 

experience as a Medical Director in SNFs. To ensure consistency across 

physician reviewers, we facilitated weekly conference calls during which 

physician reviewers discussed cases that either were complex or had possible 

implications for other cases. Additionally, a contracted geriatric psychiatrist 

provided a secondary review of select events that involved psychotropic 

medications, including falls associated with medications. 

Data Analysis 

We performed analysis and generated estimates about adverse and temporary 

harm events in three categories: national incidence of events, preventability 

of events, and Medicare cost associated with events. We included the results 

of the screener false-negative rate review in all of our analyses using 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 14 
 

 

 

 

appropriate methodology. For estimates and corresponding 95-percent 

confidence intervals, see Appendix D. 

Adverse Event Incidence Analysis. We calculated the estimated national 

adverse event incidence rate as the percentage of Medicare SNF residents 

who experienced at least one adverse event. We defined adverse events as 

events that resulted in one of the four most serious categories on a modified 

version of the NCC MERP index described above (classified on the index as 

F-I). We projected incidence rates to the population of Medicare 

beneficiaries who had SNF stays that began within 1 day of a beneficiary’s 

discharge from a hospital, had a length of stay of 35 days or less, and ended 

in August 2011. 

The overall adverse event incidence rate does not include events that 

physician reviewers identified as temporary harm events, defined as events 

that required intervention but did not cause lasting harm (classified as 

E level harm on the NCC MERP index). We excluded these temporary harm 

events from our overall rate because we determined, in consultation with 

physician reviewers, that the effect of these events was not comparable to 

those of the more serious events (i.e., F level through I level events). We 

calculated a separate incidence rate for Medicare SNF residents who 

experienced only temporary harm events. 

For beneficiaries in our sample, we also calculated 2 ratios of adverse event 

incidence density: events per 1,000 resident days and events per 100 SNF 

admissions. These measures are commonly used by providers and medical 

professionals.80 For the resulting metrics and an explanation of the methods 

used, see Appendix E. 

Preventability Analysis. The findings related to preventability are based on 

determinations made by the physician reviewers for each adverse event and 

temporary harm event. We calculated percentages for each preventability 

classification and for different types of events, the results of which are 

projectable to the population. We also conducted statistical tests to identify 

differences in preventability rates between adverse events and temporary 

harm events and across various categories of adverse events, such as 

medication-related and infection-related events. 

Medicare Cost Analysis. We estimated the cost to Medicare resulting from 

inpatient hospital stays and emergency room visits. To determine how much 

Medicare paid for services associated with events, we asked physician 

reviewers to indicate whether the SNF residents were hospitalized because 

80 K.M. Arias, Outbreak Investigation, Prevention, and Control in Health Care Settings, 

Second Edition, Jones and Bartlett Publishers, 2009, pp. 330–331. 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 15 
 

 

 

 

 

of identified adverse events. To assist them in their determinations, we 

provided the physicians with summaries of the hospital claims associated 

with each sample beneficiary. These summaries provided information on the 

hospitalizations that occurred during the SNF stays or within 14 days of the 

sample beneficiaries’ discharges from the SNFs and the diagnoses codes 

associated with the hospitalizations. 

Using hospital claims data from the NCH file and the results of the 

physicians’ medical record reviews, we identified the inpatient hospital stay 

or emergency room visit claims associated with the sample beneficiaries’ 

adverse events. We did this by matching the discharge date of the SNF stay 

with the admission date of the hospital stay or emergency room visit.81 We 

attributed the entire cost of the inpatient hospital stay or emergency room 

visit to the adverse event. We summed the reimbursements paid by 

Medicare for the hospital and emergency room claims to determine the total 

Medicare paid for the hospitalizations. 

Limitations 

The methodology presents three specific limitations. First, it is unlikely that 

the study identified all adverse and temporary harm events within the sample 

of SNF residents. To the extent that the study did not identify an event, it 

was likely because documentation in the medical records was incomplete. 

Second, cost estimates do not include all costs of care associated with 

events, including additional SNF stays caused by events but occurring after 

our sample period, additional care beyond the hospitalizations (such as 

physician office visits), and changes in Medicare RUG payments. Third, our 

sampling methodology limits our findings to beneficiaries who had SNF 

stays that ended in August 2011, began within 1 day of the beneficiaries’ 

discharges from hospitals, and were 35 days or less. 

Standards 

This study was conducted in accordance with the Quality Standards for 

Inspection and Evaluation issued by the Council of the Inspectors General 

on Integrity and Efficiency. 

81 We were not able to match one physician-identified hospitalization with a Medicare 

claim for an inpatient hospital stay or an emergency room visit. We included this transfer 

in our transfer rate but imputed the cost as zero dollars. 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 16 
 

 

 

factor t 

 

 

FINDINGS 

An estimated 22 percent of Medicare SNF residents 

experienced adverse events during their SNF stays 

Approximately one in five Medicare beneficiaries who had post-acute 

SNF stays that were 35 days or less and that ended in August 2011 

experienced at least one adverse event during their stays (22 percent).82 

For this study, an adverse event is as an event that resulted in harm 

equivalent to the four most serious categories (F-I) on our modified 

NCC MERP index (prolonged SNF stay or transfer to hospital, permanent 

harm, life-sustaining intervention, or death). We estimate that 

21,777 post-acute Medicare SNF residents experienced at least 1 adverse 

event during stays that ended in August 2011. A small portion of residents 

experienced more than one adverse event (2.6 percent), with a few of these 

residents experiencing as many as three events during a single SNF stay. 

The majority (79 percent) of the adverse events experienced by the 

Medicare SNF residents caused F level harm (see Table 2). These events 

either extended the beneficiaries’ stays in the SNFs or resulted in transfers 

from the SNFs to hospitals for acute level care, including both emergency 

department visits and inpatient admissions. Of the remaining events, 

14 percent required a life-sustaining intervention and 6 percent contributed 

to the residents’ deaths. 

Table 2: Adverse Events Classified as F-I on OIG’s Modified NCC MERP 

Index for Categorizing Adverse Events by Level of Harm 

Level of Harm Percentage of 

Adverse Events 

F level: Resulted in prolonged SNF stay, transfer to a different SNF or other 

post-acute facility, and/or hospitalization (i.e., admission to inpatient 

care, hospital observation unit, or emergency department) 

79% 

G level: Contributed to or resulted in permanent resident harm* --

H level: Required intervention to sustain the resident’s life 14% 

I level: Contributed to or resulted in resident death 6% 

See Appendix D for confidence intervals. 

*We are unable to reliably project the weighted point estimate for adverse events classified as G Level harm 

because of the small number of sample occurrences. 

Source: OIG analysis of SNF stays for 653 Medicare beneficiaries discharged in August 2011.
 

We classified the adverse events into three clinical categories: events 

related to medication (37 percent), events related to ongoing resident care 

(37 percent), and events related to infections (26 percent). Table 3 lists the 

adverse events within these three categories. See Appendix F for a list of 

82 For this study, we define “post-acute SNF stays” as SNF stays that were paid for by 

Medicare Part A under the SNF benefit, began within 1 day of beneficiaries’ discharge 

from hospitals, had lengths of stay of 35 days or less, and ended in August 2011. 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 17 
 

 

 

the 148 events with detailed descriptions and level of harm. While some 

events (such as pressure ulcers and hypoglycemia) have long been of 

concern to post-acute caregivers, we found other events (such as severe 

gastrointestinal bleeding due to anticoagulant overdose) not commonly 

associated with nursing homes. 

Table 3: Adverse Events Identified Among Medicare SNF Residents by 

Category 

Types of Adverse Events Percentage* 

Events Related to Medication 37% 

 Medication-induced delirium or other change in mental status 12% 

 Excessive bleeding due to medication 5% 

 Fall or other trauma with injury secondary to effects of medication 4% 

 Constipation, obstipation, and ileus related to medication 4% 

 Other medication events 14% 

Events Related to Resident Care 37% 

 Fall or other trauma with injury related to resident care 6% 

 Exacerbations of preexisting conditions resulting from an omission of care 6% 

 Acute kidney injury or insufficiency secondary to fluid maintenance 5% 

 Fluid and other electrolyte disorders (e.g., inadequate management of fluid) 4% 

 Venous thromboembolism, deep vein thrombosis (DVT), or pulmonary 

embolism (PE) related to resident monitoring 4% 

 Other resident care events 14% 

Events Related to Infections 26% 

 Aspiration pneumonia and other respiratory infections 10% 

 Surgical site infection (SSI) associated with wound care 5% 

 Urinary tract infection associated with catheter (CAUTI) 3% 

 Clostridium difficile infection 3% 

 Other infection events 5% 

Total 100% 

*The percentages for conditions listed within the clinical categories do not sum to 100 percent because of rounding. 

See Appendix D for percentage estimates and confidence intervals. 

See Appendix F for a complete listing of all adverse events identified by the reviewers. 

Source: OIG analysis of SNF stays for 653 Medicare beneficiaries discharged in August 2011. 

Within the sample, physician reviewers categorized some seemingly 

similar events in different clinical categories because the events or factors 

that led to the harm differed. This was most evident in the categorization 

of resident fall events; physician reviewers categorized about half of 

sample fall events as medication events and the other half as resident care 

events. The fall events categorized as medication events demonstrated 

clear evidence in the medical record that medication was the primary 

cause of the fall, because of delirium and hallucinations caused by 

psychotropic and other medications. Physician reviewers categorized the 

remaining fall events as resident care events because the falls and 

accompanying harm were the result of inadequate resident care (e.g., SNF 

staff did not adequately monitor residents who were known fall risks) 

rather than the effects of medication. 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 18 
 

The use of multiple medications often complicated the determination of 

the primary cause of events, particularly when the primary cause was 

related to another medication. For example, in one case our consulting 

geriatric psychiatrist determined that the overuse of anti-anxiety 

medication might have masked symptoms of hypoglycemia and resulted in 

a delayed diagnosis. 

An estimated 1.5 percent of Medicare SNF residents 

experienced events that contributed to their deaths 

This rate projects to an estimated 1,538 SNF residents who experienced 

adverse events that contributed to their deaths during the study 

month. Within the sample, events that contributed to deaths represented a 

wide range of adverse events from each of the three clinical categories. 

Resident care events that contributed to death included blood clots, such as 

deep vein thrombosis (DVT); fluid imbalances; and acute renal 

insufficiency. Medication events included excessive bleeding due to 

anticoagulants and acute hypoglycemia. Most of these residents died at 

hospitals rather than in the SNFs where the harm occurred, having been 

transferred back to the hospitals for higher level treatment as a result of 

the event. Some of these residents were admitted to hospitals, but others 

died in emergency departments because of the acute nature of their 

adverse events, such as cardiac arrest or excessive bleeding. 

Although no single type of event was prominent within the sample as 

contributing to death, residents who died as a result of events shared 

commonalities. Most had multiple, complex co-morbidities that physician 

reviewers determined made their care more challenging, weakened their 

conditions, or both. For example, one resident who died from a PE had a 

range of other chronic and acute conditions, including a serious infection, 

chronic heart and kidney diseases, a history of blood clots, and dementia. 

Other residents who died had previously experienced multiple instances of 

the types of events that ultimately contributed to their deaths. For 

example, one resident who died of aspiration had suffered multiple prior 

strokes that likely hampered swallowing ability. 

In the case of some resident deaths, physician reviewers found evidence in 

the medical record that the deaths may have been expected by caregivers, 

the residents, or family. In one such case, the medical record for the 

resident’s prior hospitalization showed that the hospital physician stopped 

medical intervention and suggested that the resident seek palliative care at 

the SNF. In another case of an elderly resident, the SNF medical record 

indicated that the resident’s family requested palliative care shortly before 

the resident died of cardiac arrest. Most commonly, though, death during 

the SNF stay was likely not an expected outcome, as in the case of a 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 19 
 

resident who died of cardiac arrest following progressive kidney failure 

that was not detected until the resident was awaiting discharge from the 

SNF. 

An estimated 4 percent of Medicare SNF residents experienced 

at least one “cascade” adverse event, wherein multiple, related 

events occurred in succession 

This rate projects to an estimated 3,986 residents who experienced cascade 

events during the study month. A “cascade event” is defined as an event 

that included a series of multiple, related events. We counted cascade 

events as single events. Within the sample, medication often played a 

secondary role in the cascading harm. For example, in one sample 

cascade event, a resident with multiple comorbidities, including 

neurological disorders (e.g., tremors, rigidity), and chronic kidney 

insufficiency developed significant gastrointestinal bleeding from 

excessive anticoagulation. The internal bleeding resulted in hematemesis 

(vomiting blood), which ultimately caused a fatal aspiration. Also within 

the sample, a number of cascade events began with inadequate resident 

hydration. In at least one sample case, a resident experienced significant 

dehydration followed by an electrolyte imbalance and damage to the 

kidneys because SNF staff did not actively monitor and manage the 

resident’s fluid intake. 

An additional 11 percent of Medicare SNF residents 

experienced events during their SNFs stays that 

resulted in temporary harm 

Another 11 percent of Medicare SNF residents experienced events 

classified as E level harm on the NCC MERP index (defined as resident 

harm events that required medical intervention but did not cause lasting 

harm). We estimate that 10,742 post-acute Medicare SNF residents 

experienced at least 1 temporary harm event during the study month. Of 

these beneficiaries, an estimated 2,154 had more than 1 unrelated 

event. Additionally, 21 percent of beneficiaries who experienced adverse 

events also had temporary harm events during their stays. 

As with adverse events, temporary harm events represented a wide array 

of conditions from the three clinical categories (see Table 4). Table F-2 in 

Appendix F contains a list of the 113 temporary harm events identified in 

the sample and provides detailed descriptions. 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 20 
 

 

 

 

 

 

 

Table 4: Temporary Harm Events Identified Among SNF Residents by 

Category 

Types of Temporary Harm Events Percentage* 

Events Related to Medication 43% 

 Hypoglycemic episodes (e.g., low or significant drop in blood glucose) 16% 

 Fall or other trauma with injury associated with medication 9% 

 Medication-induced delirium or other change in mental status 7% 

 Thrush and other nonsurgical infections related to medication 4% 

 Allergic reactions to medications (e.g., rash, itching) 3% 

 Other medication events 3% 

Events Related to Resident Care 40% 

 Pressure ulcers 19% 

 Fall or other trauma with injury associated with resident care 8% 

 Skin tear, abrasion, or breakdown 7% 

 Other resident care events 6% 

Events Related to Infections 17% 

 CAUTI 5% 

 SSI associated with wound care 5% 

 Other infection events 7% 

Total 100% 

*The percentages for conditions listed within the clinical categories do not sum to 100 percent because of rounding. 

See Appendix D for percentage estimates and confidence intervals. 

See Appendix F for a complete listing of all temporary harm events identified by the reviewers. 

Source: OIG analysis of SNF stays for 653 Medicare beneficiaries discharged in August 2011. 

Although many cases of temporary harm within the sample represented 

instances of fairly minor harm to the residents, other temporary harm 

events caused harm that was significant for the residents. We did not 

classify these events as adverse events because they did not require 

transfer to a hospital or prolong the SNF stays. Additionally, physician 

reviewers indicated that many sample temporary harm events could have 

developed into more serious events if SNF staff had not provided a timely 

intervention. For example, infection events such as Clostridium difficile 

and CAUTIs can quickly escalate from infections to serious, 

life-threatening infections if not diagnosed and treated quickly.83, 84 

83 L.A. Mermel, “Reducing Clostridium difficile incidence, colectomies, and mortality in 

the hospital setting: a successful multidisciplinary approach,” Joint Commission Journal 

of Quality and Patient Safety, 39, 7, 2013: pp. 298-305. 84 Centers for Disease Control and Prevention (CDC), Inpatient Care of Septicemia or 

Sepsis: A Challenge for Patients and Hospitals, National Center for Health Statistics 

Data Brief, 2011. 

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Physician reviewers determined that 59 percent of 

adverse events and temporary harm events were 

clearly or likely preventable 

Physician reviewers assessed the extent to which events were preventable 

on the basis of information in the medical records, their clinical experience 

with similar circumstances, research literature about specific events, and 

group discussion to reach consensus. Combining adverse events and 

temporary harm events, physicians determined that 59 percent were 

preventable and 37 percent were not preventable. For the 

remaining 4 percent, physicians were unable to make determinations 

because of incomplete documentation in the medical records or extreme 

complexities in the residents’ conditions or in the care provided. Table 

5 provides the percentage of events by preventability assessment for 

adverse events, temporary harm events, and both groups of events 

combined. 

Table 5: Adverse and Temporary Harm Events by Preventability 

Determination 

Preventability Assessment 

Percentage of 

Adverse 

Events 

Percentage of 

Temporary 

Harm Events 

Percentage 

of All 

 Events 

Preventable—Harm could have been avoided 

through improved assessment or alternative 

actions 

Clearly preventable 

Likely preventable 

69%

18%

50%

 46% 

6% 

40% 

59% 

13% 

46% 

Not preventable—Harm could not have been 

avoided given the complexity of the resident’s 

condition or care required 

Clearly not preventable 

Likely not preventable 

29%

11%

18%

 47% 

12% 

35% 

37% 

11% 

26% 

Unable To Determine Preventability* 3% -- 4.2% 

*We are unable to reliably project the weighted point estimate for temporary harm events classified as “Unable to
 

Determine” because of the small number of sample occurrences. 

Source: OIG analysis of SNF stays for 653 Medicare beneficiaries discharged in August 2011.
 

Physicians determined that a larger percentage of adverse events was 

preventable (69 percent) than temporary harm events (46 percent).85 If we 

were to include only preventable events in the estimated incidence rate of 

adverse events among Medicare beneficiaries, the adverse event rate 

would be 15 percent (rather than 22 percent) and the rate of additional 

beneficiaries experiencing temporary harm events would be 5 percent 

(rather than 11 percent). Physician reviewers determined that 66 percent 

of medication events were preventable, 57 percent of resident care events 

85 The ratio of preventable adverse events to adverse events was statistically higher than 

the ratio of preventable temporary harm events to temporary harm events at the 

95-percent confidence level. 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 22 
 

 

were preventable, and 52 percent of infection events were preventable. 

Table 6 provides the percentage of preventable events by clinical category. 

Table 6: Percentage of Preventable Adverse and Temporary Harm Events 

by Clinical Category 

Types of Adverse and Temporary Harm Events 

Percentage of Preventable 

Adverse and Temporary 

Harm Events (n = 155) 

Events Related to Medication 66% 

Events Related to Resident Care 57% 

Events Related to Infections 52% 

Source: OIG analysis of SNF stays for 653 Medicare beneficiaries discharged in August 2011. 

Within the clinical categories, physician reviewers often gave the same 

preventability assessment to events with similar circumstances. In making 

preventability determinations for specific cases, physicians factored in 

both the residents’ condition and the adequacy of SNF monitoring and 

interventions. For example, all cases of hypotension in the sample were 

considered preventable because all the residents developed the condition 

because of insufficient monitoring. Similarly, all allergic reactions 

identified in the sample were considered not preventable because the 

residents’ medical records lacked historical information about allergies. 

In other cases, similar events had different preventability determinations, 

often because of variation in the health of SNF residents involved. For 

example, reviewers described pressure ulcers as preventable when the 

resident was generally healthy and able to comply with pressure ulcer 

precautions (e.g., frequent rotation of the resident) but received inadequate 

evidence-based pressure ulcer precautions. They described pressure ulcers 

as not preventable when they found evidence that the resident received 

evidence-based preventative pressure ulcer care but developed the ulcers 

because of comorbidities that greatly increased their risk of developing 

pressure ulcers. Physician reviewers reported that these comorbidities 

made it difficult for SNF staff to provide the type of care typically used to 

prevent such ulcers. As another example, among sample cases of 

aspiration pneumonia, physicians determined preventability on the basis of 

resident conditions that may not respond well to treatments, such as 

chronic dysphagia (difficulty in swallowing). Among hypoglycemic 

episodes, physicians determined similar cases as preventable on the basis 

of factors such as the residents’ past experience with wide variance in 

blood glucose levels and staff use of appropriate insulin dosing regimens. 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 23 
 

Factors that contributed to preventable adverse and temporary 

harm events included substandard treatment, inadequate 

resident monitoring, and failing to provide treatments 

Physician reviewers selected one or more rationales to support each 

preventability determination from a list developed by the physician panel. 

To make these selections, physicians gleaned information from medical 

records, such as staff actions, environmental factors, and resident 

condition unrelated to the event. Among preventable events, 37 percent 

involved inadequate monitoring of the residents and 25 percent involved 

failure to provide necessary treatments. One sample resident suffered an 

undiagnosed pneumothorax (collapsed lung) because of SNF staff failure 

to recognize symptoms of shoulder pain and shortness of breath. The 

resident later had two additional events, a reaction to medication and a 

blood clot, both requiring transfer to a hospital. Table 7 provides 

preventability rationales for events within the preventable and not 

preventable assessment categories. 

Table 7: Adverse and Temporary Harm Events by Preventability

Rationales 

Adverse and Temporary Harm Preventability Rationale Percentage* 

Preventable Events 

Appropriate treatment was provided in a substandard way 56% 

The resident’s progress was not adequately monitored 37% 

Necessary treatment was not provided 25% 

Error was related to medical judgment, skill, or resident management 14% 

Resident care plan was inadequate 11% 

Care plan was incomplete or not sufficient in describing resident’s condition 7% 

The resident’s health status was not adequately assessed 4% 

Not Preventable Events 

Resident was highly susceptible to event because of health status 59% 

Event occurred despite proper assessment and procedures followed 32% 

Resident’s diagnosis was unusual or complex, making care difficult 27% 

Care provider could not have anticipated event given information available 20% 

*Percentages do not add to 100 because physician reviewers often selected more than one rationale. 

See Appendix D for confidence intervals. 

Source: OIG analysis of SNF stays for 653 Medicare beneficiaries discharged in August 2011.
 

Not preventable events involved residents who were highly 

susceptible or otherwise at risk for experiencing harm despite 

efforts by staff to avoid harm 

In these cases, physicians determined that the care provided was sufficient 

and appropriate and that there was no evidence of errors or other 

problems. In some of these cases, necessary treatment resulted in harmful 

side effects. For example, one elderly resident in our sample experienced 

delirium from needed pain medications given following surgery and 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 24 
 

 

 

 

 

another experienced gastrointestinal bleeding from anticoagulants 

prescribed for a heart condition. In other cases, resident care decisions 

made in the prior hospitalization resulted in harm during the SNF stay. In 

one case, a resident developed a full body rash several days into the stay 

that was an allergic reaction to an antibiotic that had been prescribed in the 

preceding hospitalization and was continued in the SNF. In other cases of 

not preventable adverse events, the SNF residents or families contributed 

to the events by not complying with staff recommendations. For example, 

one sample resident with Alzheimer’s-related dementia fractured his hip 

while attempting to stand without assistance and another resident pulled 

out his feeding tube, ultimately causing an infection at the insertion site. 

For 59 percent of the not preventable events, physician reviewers found 

that residents’ comorbidities or health status made them highly susceptible 

to the events. Within our sample, aspiration pneumonia events were a 

prominent example. Many of the sample beneficiaries who experienced 

these events were highly susceptible to aspiration because they had 

comorbidities that made it difficult for them to swallow. In one such case, 

a resident with significant difficulty swallowing because of neurological 

disorders (tremors, rigidity) aspirated despite a thorough evaluation and 

with aspiration precautions in place (substituting liquid food for solid).86 

Over half of the residents who experienced harm went 

to a hospital for treatment, with an estimated cost to 

Medicare of $208 million in August 2011 

Adverse events that occurred in post-acute SNF stays of less than 36 days 

ending in August 2011 resulted in an estimated 20,393 resident transfers to 

hospitals and an estimated $208 million in Medicare expenditures for 

these hospitalizations.87 Of the estimated $208 million spent on all 

hospitalizations, $136 million was spent on hospitalizations associated 

with preventable events. The estimate of $208 million spent on care 

associated with all adverse events equates to 2 percent of the $10.2 billion 

that Medicare spent on inpatient hospital stays in August 2011.88 

86 The study methodology did not include an analysis of end-of-life care issues, such as 

instructions from residents and families to not resuscitate residents in the event of a poor 

condition. However, when these factors were present in the medical record, physician 

reviewers considered them in determining preventability. For example, when the SNF 

record included a signed order to provide only palliative care or included notes regarding 

a discussion of such care with the resident or family, physician reviewers weighed that 

obligation against any inadequacies in the provision of care leading up to the harm event. 87 For this study, we define “hospitalization” as any transfer to a hospital for an inpatient 

admission, emergency department visit, or observation unit stay. 

88 The August 2011 Medicare inpatient cost figure is from OIG analysis of August 2011
 

Medicare hospital claims, NCH file. 

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Assuming that the rate of Medicare spending on hospitalizations due to 

adverse events in SNFs remained constant throughout the year, 2 percent 

of the $140 billion Medicare inpatient expenditures equates to $2.8 billion 

spent in FY 2011 on hospitalizations associated with preventable and not 

preventable adverse events that occurred in SNFs.89 

Of the estimated 32,519 Medicare SNF residents who experienced at least 

1 adverse or temporary harm event, an estimated 19,470 (60 percent) were 

hospitalized at least once as a result of the events. The hospitalized 

residents constitute 19 percent of all Medicare beneficiaries in SNF stays 

that were 35 days or less and that ended in August 2011.90 Because some 

SNF residents were hospitalized more than once, the total number of 

hospitalizations resulting from adverse events was 20,393. Within our 

sample, infection-related events resulted in the fewest hospitalizations 

among the three clinical categories but incurred the highest cost per 

hospitalization (see Table 8). 

Table 8: Costs of Hospitalizations Associated With Adverse Events 

Hospitalization Type 

Estimated 

Number of 

Hospitalizations 

Estimated 

Average 

Costs 

Estimated 

Total 

Spending 

Hospitalizations for medication events 7,203 $8,372 $57,729,935 

Hospitalizations for resident care events 7,511 $8,967 $67,350,098 

Hospitalizations for infections events 5,679 $14,599 $82,899,180 

Hospitalizations Associated With All Events 20,393 $10,276 $207,979,213 

Source: OIG analysis of SNF stays for 653 Medicare beneficiaries discharged in August 2011. 

Within the sample, certain types of events frequently led to 

hospitalizations. For example, all sample aspiration pneumonia events led 

to hospitalization. For most of these sample events, the medical records 

indicated that SNF staff hospitalized the residents because the care needed 

to ameliorate the respiratory distress caused by the aspiration exceeded the 

level of care they could provide. 

The full costs associated with these events are likely greater than our 

estimate. Our cost estimate is a projection of reimbursements paid by 

Medicare Part A for the hospitalizations associated with the identified 

adverse events and by Medicare Part B for emergency room visits. It does 

89 The annual cost estimate of $2.8 billion is 2 percent of the $140 billion Medicare 

inpatient costs for FY 2011, which assumes the same proportion of costs for adverse 

events for the other 11 months that we found in August 2011. Annual Medicare inpatient 

cost figure is from CMS, 2011 CMS Statistics Book, Table III.6, Office of Research, 

Development, and Information, CMS Pub. No. 03504, June 2011, p. 30. 

90 The remaining Medicare SNF residents either did not experience adverse events or 

temporary harm events, experienced events that did not lead to hospitalization, were 

hospitalized for other reasons, or died during their SNF stays. 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 26 
 

not include any other costs paid by Medicare or by other payers— 

including beneficiaries—for medical care needed as a result of the adverse 

events or temporary harm events. 

CONCLUSION AND RECOMMENDATIONS 

The ACA mandated HHS to establish and follow a national strategy for 

quality improvement in health care, including patient and resident safety. 

Post-acute care in SNFs is intended to help beneficiaries improve health 

and functioning following a hospitalization and is second only to hospital 

care among inpatient costs to Medicare. While health care stakeholders 

have in recent years given substantial attention to patient safety in 

hospitals, less is known about resident safety in SNFs. 

Replicating the methods we used in the 2010 OIG study of hospital 

adverse events, this report provides the first national incidence rate of 

adverse events in SNFs. Twenty-two percent of Medicare beneficiaries 

experienced adverse events during their SNF stays, resulting in prolonged 

SNFs stays or hospitalizations, permanent harm, life-sustaining 

intervention, or death. An additional 11 percent experienced temporary 

harm events. This 32-percent total harm rate is similar to what OIG found 

in its 2010 hospital report, which stated that 27 percent of Medicare 

beneficiaries had experienced adverse and temporary harm events during 

their hospital stays. Also, 59 percent of events in SNFs were preventable, 

and hospitalizations necessitated by the events increased costs to Medicare 

by an estimated $208 million in a single month, suggesting potential 

savings from reducing the incidence of adverse events that occur in SNFs. 

Because more than half of the adverse events that we identified were 

preventable, our study confirms the need and opportunity for SNFs to 

significantly reduce the incidence of events. This reduction in events and 

improved safety for post-acute residents would require a coordinated 

response to include both providers and overseers. A number of agencies 

within HHS share responsibility for addressing this issue, most 

prominently AHRQ as a coordinating body for efforts to improve health 

care quality and CMS as the Nation’s largest health care payer and an 

oversight entity. 

Therefore, we recommend the following: 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 27 
 

 

 

AHRQ and CMS should raise awareness of adverse events in 

post-acute care and seek to reduce harm to nursing home 

residents through methods used to promote hospital safety 

In response to recent OIG recommendations to reduce adverse events in 

hospitals, AHRQ and CMS are collaborating to create a list of potentially 

reportable adverse events for hospital staff education and facility 

measurement. CMS also developed hospital surveyor training to assist 

hospital overseers in assessing safety practices, and AHRQ has refined the 

process for submitting event reports to PSOs. Broadening these and other 

patient safety improvement efforts to include the nursing home 

environment would ensure that safe care practices promoted in acute care 

hospitals extend to the critical period of post-acute recovery.91 Agency 

response to this recommendation should include the following: 

	 AHRQ and CMS should collaborate to create and promote a 

list of potential nursing home events 

Staff identification of resident harm is critical to the success of 

resident safety efforts, giving them the opportunity to correct problems 

and reduce harm as well as to report problems contributing to events. 

Our physician review of medical records found that many events were 

the result of failure by SNF staff to monitor residents or staff delay in 

providing necessary medical care. AHRQ and CMS should ensure 

that nursing home staff are able to identify resident harm events to 

prevent harm or worsening. Additionally, we found events not 

commonly associated with nursing homes that therefore may not have 

been included in staff training efforts. 

To inform nursing homes about the range of potential adverse events, 

AHRQ and CMS should collaborate to create and promote a list of 

potentially reportable events for nursing homes. The list would 

educate SNF staff about the full range of resident harm. The list 

should go beyond the conventional SNF care issues and include a 

comprehensive range of possible resident harm. Events could include 

those identified in this report and by other researchers, recognizing the 

unique challenges of the SNF setting rather than duplicating lists of 

hospital events. AHRQ and CMS should be clear that they do not 

require external nursing home reporting of these events, but provide 

the list to broaden and improve staff understanding. 

91 We specify that these efforts should be directed to all nursing homes rather than only to 

post-acute care in SNFs, given that AHRQ and CMS guidance and CMS oversight 

authority extend to all nursing home stays. 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 28 
 

 

 

 

	 CMS should include potential events and information about 

resident harm in its quality guidance to nursing homes 

Under the ACA, nursing homes must develop QAPI programs to 

address quality problems and improve facility performance. In 2013, 

CMS began to provide new guidance to nursing homes to encourage 

effective QAPI development and implementation. The initial 

guidance, released in July 2013, focused on core elements needed to 

improve practices, such as goal-setting. CMS has indicated that 

subsequent materials to be released in 2014 will provide information 

specific to clinical care and resident safety. CMS should ensure that 

the guidance includes elements similar to what it has promulgated to 

hospitals, including a definition of “adverse events,” a list of potential 

adverse events for staff education on the range of harm that residents 

can experience, strategies for detecting and measuring adverse events, 

and best practices for improving staff recognition and reporting of 

adverse events. Issuing similar guidance to both hospitals and nursing 

homes may improve communication and collaboration regarding 

shared safety concerns and care transitions as prescribed in the ACA. 

	 AHRQ and CMS should encourage nursing homes to report 

adverse events to Patient Safety Organizations 

Nursing home reporting to PSOs would enable the post-acute 

community to gain from the structure already in place for the hospital 

community. Routine reporting by nursing homes could help establish 

the process of event identification within facilities, and the resulting 

PSO analysis of nursing home events would provide much-needed 

information that would be useful in quality and safety improvement 

efforts. Analysis of events across facilities assists providers in 

directing resources to the areas of greatest need, setting clear goals for 

improvement, assessing the effectiveness of specific strategies, 

holding nursing homes accountable, and gauging progress in reducing 

incidence. 

Encouraging nursing home reporting to PSOs will require efforts on 

the part of both agencies to adapt processes to the nursing home setting 

and to reduce barriers to reporting. AHRQ has designed PSO 

reporting formats for the nursing home setting, and a number of PSOs 

accept adverse event reports from post-acute care providers. AHRQ 

and CMS should build on these initial steps by conducting outreach to 

nursing homes about event reporting, promoting the reporting of 

adverse events by nursing homes to PSOs, and gaining knowledge 

about the nature and type of information and assistance that would be 

most helpful to nursing homes. AHRQ and CMS should also 

collaborate to resolve any barriers to nursing home reporting due to 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 29 
 

 

 

 

possible conflicts between QAPI provisions that require nursing homes 

to share event information with State agency surveyors and PSO 

provisions that require confidentiality of reported information. 

CMS should instruct nursing home surveyors to review facility 

practices for identifying and reducing adverse events 

Federal requirements regarding resident safety in SNFs include both 

broad, facilitywide mandates, as well as requirements specific to certain 

practices. These requirements are tied largely to nursing home QAPI 

programs and governed by the facilities’ QAA committees. CMS should 

instruct State survey agencies to include an assessment of adverse event 

identification and reduction in their evaluations of QAPI and QAA 

compliance and link related deficiencies specifically to resident safety 

practices. This link would provide an incentive to nursing homes to 

develop strategies to reduce adverse events. To facilitate State agency 

assessment of QAPI programs, QAA committee activities, and other 

nursing home activities related to adverse events, we recommend that this 

guidance include information about how surveyors should assess nursing 

home adverse event collection efforts and should include the list of 

potentially reportable events to be developed by AHRQ and CMS. 

AGENCY COMMENTS AND OFFICE OF INSPECTOR GENERAL 

RESPONSE 

We received comments on the draft report from AHRQ and CMS. 

AHRQ. AHRQ concurred with our recommendations. AHRQ stated that 

the information presented in the report will help improve the care provided 

to an “especially vulnerable patient population.” 

In response to our sub-recommendation that AHRQ and CMS collaborate 

to create and promote a list of potential nursing home events, AHRQ 

stated that it will use information about the 261 events identified in our 

report as it develops the next version of the Common Formats. 

In response to our sub-recommendation that AHRQ and CMS encourage 

nursing homes to report adverse events to PSOs, AHRQ stated that it will 

increase its emphasis on this organizational priority. In particular, AHRQ 

will conduct outreach to organizations representing nursing homes to 

increase awareness of PSOs. AHRQ also noted that it is working with 

CMS on the 11th Scope of Work for Quality Improvement Organizations, 

specifically to resolve issues related to nursing home event reporting. 

CMS. CMS concurred with our recommendations. CMS stated that it 

recognizes the importance of identifying adverse events among nursing 

home residents as a way to improve resident quality of life and medical 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 30 
 

care. In its comments, CMS provided details about current activities and 

future plans to improve nursing home resident safety. 

In response to our recommendation that AHRQ and CMS raise awareness 

of adverse events in post-acute care and seek to reduce harm to nursing 

home residents through methods used to promote hospital safety, CMS 

agreed that helping nursing homes better understand what constitutes an 

adverse event could reduce preventable harm. CMS also agreed that it 

would be instructive to review methods used by hospitals to reduce 

adverse events. CMS indicated that activities underway to establish 

specific QAPI requirements for nursing homes may raise awareness of 

adverse events. These activities include CMS development of technical 

guidance on QAPI and release of the guidance to nursing homes. 

In response to our sub-recommendation that AHRQ and CMS collaborate 

to create and promote a list of potential nursing home events, CMS stated 

that it will work with AHRQ to develop a common definition and 

description of adverse events. CMS also stated that it intends to use the 

results of the OIG’s review to build a list of potential adverse events. 

In response to our sub-recommendation that CMS include potential events 

and information about resident harm in its quality guidance to nursing 

homes, CMS stated that it will include guidance on adverse events and a 

list of potential events in its QAPI technical assistance and make this 

available through the nursing home QAPI Web page. 

In response to our sub-recommendation that AHRQ and CMS encourage 

nursing homes to report to PSOs, CMS concurred conditionally. CMS 

stated that while it believes PSOs can help nursing homes improve their 

performance improvement capabilities, it is concerned that the 

confidentiality and privilege protections outlined in the legislation that 

created the PSOs—the Patient Safety and Quality Improvement Act of 

2005—could make it difficult for surveyors to adequately assess nursing 

home QAPI programs. Therefore, CMS stated that in implementing the 

sub-recommendation, it would work with AHRQ to ensure preservation of 

both the survey and certification function and the confidentiality and 

privilege protections afforded by PSOs. 

In response to our recommendation that CMS instruct nursing home 

surveyors to review facility practices for identifying and reducing adverse 

events, CMS stated that activities underway to establish QAPI 

requirements for nursing homes will include guidance for surveyors on 

how to evaluate nursing home efforts to identify and reduce adverse 

events. 

For the full text of AHRQ and CMS comments, see Appendix G. 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 31 
 

APPENDIX A 

Glossary of Select Medical Terms92 

Adverse event—Harm to a patient or resident as a result of medical care 

or in a health care setting. For purposes of calculating an incidence rate 

for this study, we defined “adverse events” as events that resulted in one of 

the four most serious categories on our modified version of the NCC 

MERP Patient Harm Index (classified on the index as F-I): prolonged 

SNF stay or hospitalizations (including emergency room visit), permanent 

harm, life-sustaining intervention, or death. 

Anticoagulant—A drug that hinders blood coagulation, typically used to 

prevent or treat blood clots. 

Aspiration—Accidental inhalation of foreign material into the lungs, such 

as food and/or gastric contents. 

Aspiration pneumonia—An infectious process caused by the inhalation 

of oropharyngeal secretions (food, liquid, or gastric contents) that are 

colonized by pathogenic bacteria. 

Blood clot—A coagulated mass that can occlude an artery or vein. 

Comorbidity—The presence or effect of one or more diseases or 

disorders in addition to a primary disease or disorder. 

Chronic kidney insufficiency—Slow loss of kidney function over time. 

Deep vein thrombosis or DVT—A condition marked by the formation of 

a thrombus (blood clot) within a deep vein (as of the leg or pelvis) that is 

potentially life threatening if dislodgment of the thrombus results in 

pulmonary embolism blocking the pulmonary (lung) artery. 

Fluid and electrolyte balance—Minerals in the body that have an electric 

charge and are in body fluids, such as Sodium (Na+) and Potassium (K+). 

Maintaining the right balance of electrolytes helps maintain normal 

biochemical and physiological functions. 

Gastrointestinal (GI) bleeding—Bleeding from one or more areas of the 

digestive or GI tract. 

Hypertension—Abnormally high arterial blood pressure that typically 

results in a thickening of arterial walls and is a risk factor for various 

92 Clinical definitions adapted from the National Institutes of Health, U.S. National 

Library of Medicine, Medline Plus Medical Dictionary. Accessed at 

http://www.nlm.nih.gov on May 5, 2013. 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 32 
 

pathological conditions or events (such as heart attack, heart failure, 

stroke, end-stage renal disease, or retinal hemorrhage). 

Hypoglycemia—An abnormal decrease in blood sugar in the blood. 

Hypotension—Abnormally low blood pressure. 

Ileostomy—The bottom of the small intestine (ileum) attached to the 

stoma; bypasses the colon, rectum, and anus. 

Ileus—Hypomotility of the gastrointestinal tract in the absence of 

mechanical bowel obstruction; specifically, a condition that is commonly 

marked by a painful distended abdomen, vomiting, toxemia, and 

dehydration when intestinal contents back up. 

Ketoacidosis—A condition in which the body cannot use sugar (glucose) 

for energy because there is no insulin or not enough insulin; fat is used for 

energy instead. During ketoacidosis, ketones build up in the blood and 

urine. In high levels, ketones are poisonous and potentially life 

threatening. 

Pressure ulcer—An ulceration of tissue deprived of adequate blood 

supply by prolonged pressure; also called decubitus ulcer and bedsore. 

Sepsis—A systemic response typically to a serious, usually localized, 

infection (in the urinary tract or lungs), especially of bacterial origin. 

Septicemia—Presence of virulent microorganisms, such as bacteria, virus, 

or fungi from an infection accompanied by acute systemic illness. 

Temporary harm event—Patient or resident harm event that required 

intervention but did not cause lasting harm, a prolongation of medical stay, 

or death or require a life-sustaining intervention; classified as E level of 

harm on the NCC MERP index. 

Thrush—Yeast infection that causes white patches in mouth, in the GI 

tract, and in other mucocutaneous junctions. 

Urinary tract infection (UTI)—An infection of the tract through which 

urine passes and which consists of the renal tubules and renal pelvis of the 

kidney, the ureters, the bladder, and the urethra. 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 33 
 

APPENDIX B 

Methodology for Identifying Events and Determining 

Preventability 

We conducted a two-stage medical record review to identify adverse and 

temporary harm events. In the first stage, a nurse practitioner and four 

registered nurses (referred to as “screeners”) identified sample beneficiaries 

who were likely to have experienced adverse and temporary harm events 

during their SNF stays. In the second stage, physicians identified adverse 

and temporary harm events in the records of the subset of beneficiaries who 

were determined by the screeners as likely to have experienced adverse or 

temporary harm events and in the records of those selected as part of an 

assessment of the screener efficacy. 

Screening for Beneficiaries Who Likely Experienced Harm Events. To 

identify beneficiaries who were likely to have experienced adverse and 

temporary harm events during their SNF stays, contracted screeners 

reviewed the following: complete medical records from the SNF stays; 

resident assessment data (i.e., Minimum Data Set) collected during the SNF 

stay; discharge summaries, lab results, and other key documents from the 

medical records of the hospital stays that preceded the SNF stays; discharge 

summaries, lab results, and other key documents from the medical records of 

the hospital stays or emergency room visits that occurred during the SNF 

stays or within 14 days of the SNF discharge dates; and administrative and 

billing data from the preceding and subsequent hospital stays. From the 

SNF resident assessment data, we extracted information about each 

resident’s health status during the stays, any chronic illnesses, rehabilitation 

progress, and possible medical concerns (e.g., risk of falling, developing a 

pressure ulcer). From hospital claims data, we extracted administrative data 

(e.g., admission and discharge dates), diagnosis and procedure codes, and 

information on the reimbursements paid by Medicare for the hospital stays. 

The screeners reviewed the documents and data from the preceding and 

subsequent hospital stays to look for evidence of events that occurred during 

the SNF stays. A beneficiary was considered likely to have experienced an 

adverse or temporary harm event if the screeners found at least one potential 

event during any of the beneficiary’s hospital stays. Of the 653 beneficiaries 

in the sample, the screeners “flagged” 262 beneficiaries’ (40 percent) records 

for physician review. 

To standardize their review, we required the screeners to use an 

OIG-developed protocol—the SNF Trigger Tool—to identify triggers in the 

medical record. These triggers are indicators of possible adverse and 

temporary harm events. If the screeners found a trigger, they explored the 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 34 
 

 

record further to determine whether events occurred and, if so, documented 

the level of harm. 

The screening process enabled us to reduce the number of cases requiring 

second-level review of the full medical records by a physician. The 

physician reviewers indicated that the results of the screening methods 

helped them to readily identify potential adverse and temporary harm events 

for consideration. 

Determining a Screener False-Negative Rate. In addition to reviewing the 

records associated with the 262 beneficiaries flagged by the screeners, the 

physicians also reviewed the records of 100 beneficiaries randomly selected 

from 391 beneficiaries who were not flagged by the screeners. The 

physicians reviewed these records to determine the rate at which the 

screeners failed to identify beneficiaries who likely experienced adverse or 

temporary harm events. The physician reviewers found harm events not 

otherwise found by the screeners in 7 of the 100 randomly selected 

beneficiaries’ records. These events are noted in Appendix F. 

Physician Identification of Events Within SNF Records. Five contracted 

physicians independently reviewed the medical records of the 

362 beneficiaries flagged by either the screening method or selected as part 

of the screener false-negative rate review. The physician reviewers 

represented a variety of specializations and experience: an infectious disease 

specialist, a cardiologist, an orthopedic surgeon, an internal medicine 

specialist, and a geriatrician with extensive experience as a SNF medical 

director. All five had many years of clinical experience, and four had prior 

experience in detecting adverse and temporary harm events in retrospective 

medical record review. Four of the five served as physician reviewers for a 

2010 OIG study of adverse events in hospitals. 

To identify adverse and temporary harm events experienced by the SNF 

residents during their SNF stays, the physicians reviewed all the information 

made available to the screeners as well as the results of the screeners’ 

reviews. In addition to reviewing the SNF records, the physicians reviewed 

the documents and data from the preceding and subsequent hospital stays to 

look for evidence of events that occurred during the SNF stays. 

Over 20 weeks, the physician reviewers examined the records of the 362 

beneficiaries. Each case was reviewed by one physician. Physician 

reviewers used a structured medical review protocol that required them to 

describe each adverse event, list the parts of the medical record that 

contained evidence of the event, and specify the level of harm experienced 

by the patient. Harm was categorized in accordance with a modified version 

of the NCC MERP Index of Categorizing Medication Errors. The modified 

version of the NCC MERP index is in Table B-1. 

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Table B-1: Modified Version of the NCC MERP Index for Categorizing 

Errors Used in the OIG study of Adverse Events in SNFs 

Level Description Category 

E Harm occurred that caused temporary harm that required intervention. Temporary 

Harm Event 

F 

Harm occurred that prolonged the SNF stay and led to a transfer to a 

different SNF or other post-acute facility and/or hospitalization 

(i.e., admission to a hospital observation unit, an emergency department, or 

inpatient care). Adverse 

G Harm occurred that contributed to or resulted in permanent resident harm. Event

H Harm occurred that required intervention to sustain the resident’s life. 

I Harm occurred that may have contributed to or resulted in resident death. 

Source: Modified version of the NCC MERP Index for Categorizing Errors, Medication Errors Council Revises and 

Expands Index for Categorizing Errors: Definitions of Medication Errors Broadened, Press Release, June 12, 2001. 

We recorded all harm events identified by the physician reviewers as 

occurring during the SNF stays and attributable to SNF care. We excluded 

all harm events that occurred before the beneficiary entered the SNF and all 

events attributable to the care provided in the preceding hospitalization. 

When an initial event caused a series of related and dependent events, we 

collapsed the events into a “cascade event” and counted it as a single event.93 

When a resident experienced a specific type of event more than once during 

a stay (e.g., two episodes of hypoglycemia), we counted them as a single 

event if the second event reoccurred within 7 days of the first event and 

occurred under the same circumstances. We counted them as separate events 

if the second event reoccurred more than 7 days after the first event or the 

circumstances that led to the event were substantially different. 

Determining Preventability for Each Event. The physician reviewers 

included an assessment of the extent to which events were preventable and 

factors that contributed to events. They used a five-point response scale: 

	 Clearly Preventable—Resident harm could definitely have been 

avoided through improved assessment or alternative actions. 

	 Likely Preventable—Resident harm could have been avoided through 

improved assessment or alternative actions. 

	 Likely Not Preventable—Resident harm could not have been avoided 

given the complexity of the resident’s condition or the care required. 

	 Clearly Not Preventable—Resident harm could definitely not have 

been avoided given the complexity of the resident’s condition or the 

care required. 

93 On the basis of OIG interviews with IHI staff, a “cascade event” is defined as an initial 

event that causes a series of related events for the same patient and results in collapsing 

these into a single event. 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 36 
 

 Unable To Determine—Physicians were unable to determine 

preventability because of incomplete documentation or case 

complexity. 

Assessing an event as clearly preventable or clearly not preventable required 

a greater degree of certainty on the part of the reviewer. The expanded scale 

enabled physicians to make more precise determinations, while our primary 

statistics collapse clearly and likely. Physician reviewers used a uniform 

method to improve consistency in making preventability determinations. We 

worked with the reviewers to develop a decision algorithm during practice 

reviews consisting of a series of questions that led the reviewers to a 

suggested response. Questions addressed issues such as whether there was a 

medical error, whether the event could have been anticipated, and how 

frequently the event occurred given proper care. Physicians did not 

automatically accept the suggested response, but determined whether it was 

appropriate in the particular case. Figure B-1 on the next page illustrates the 

review process for determining preventability. 

To make distinctions about the circumstances in each case, physicians used 

their clinical experience and judgment. They considered all evidence in the 

medical records, including staff actions and the resident’s condition. 

Physicians also used information about accepted standards of care, the 

frequency with which certain events occurred despite appropriate assessment 

and care, the physicians’ individual clinical experiences, guidance developed 

during the review process, and group discussion of cases. Using a list of 

contributing factors gleaned from prior research and experience in prior OIG 

studies of adverse event incidence, physicians indicated the rationale for 

each determination and provided a narrative description for each case. 

The list of contributing factors included broad concepts from the decision 

algorithm, such as errors, but also more nuanced factors, such as whether the 

resident was monitored or was susceptible to the event. To identify the 

factors that contributed to the events and assess preventability, physicians 

relied on information provided in the medical record about the residents’ 

conditions and actions of health care providers, supplemented by their own 

clinical expertise. Physician reviewers used published research and policy 

guidance regarding evidence-based guidelines and associated standards of 

care. 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 37 
 

Figure B-1: Physician Review Process for Determining 

Preventability 

Consistency Discussions and Review. Throughout our medical records 

review, we facilitated 17 conference calls during which the physician 

reviewers discussed the review protocol and sample cases that either were 

complex or had possible implications for other cases. The goal of these calls 

was to reach consensus on difficult and complex cases and to establish 

consistency between reviewers. On the calls, the physicians solicited the 

opinions of the other panelists and used the conclusions of their discussions 

to make determinations on difficult cases. We required that physicians 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 38 
 

 

 

 

discuss all clearly preventable determinations and events that potentially 

contributed to a resident’s death during the weekly conference calls, and we 

encouraged them to bring other cases for discussion if they had difficulty or 

felt the cases would inform other determinations. Physicians also often 

brought cases to group discussion if they involved care specific to a 

specialization of another physician. We documented the discussions and 

conclusions made during these weekly calls, continually revising a written 

physician guidance document to further promote consistency. The 

physicians reviewed or discussed the majority of the identified events as 

well as possible events, which the group ultimately determined did not meet 

the study threshold. 

Following the medical records review, we analyzed the identified events, 

harm-level determinations, and preventability determinations to identify any 

inconsistencies and discussed these with physician reviewers. This process 

resulted in changes to the initial determinations of some events. 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 39 
 

 

APPENDIX C 

Development and Description of the SNF Trigger Tool 

In preparation for this study, OIG built a trigger tool for screening SNF 

medical records. We refer to this tool as the “SNF Trigger Tool.” For 

studies of adverse events in hospitals in 2008 and 2010, OIG used a 

modified version of the IHI’s GTT. The IHI GTT is a 20-minute review 

of medical records that identifies “triggers” signaling possible resident 

harm and then identifies adverse and temporary harm events on the basis 

of evidence in the records. A trigger could be a description of the harm 

itself or a reference that indicates harm occurred (such as a return to 

surgery). The IHI GTT is to be completed by nurses. The results are then 

to be confirmed or refuted by a physician. The IHI GTT is designed to be 

specific to acute care medical records. 

OIG developed a SNF Trigger Tool to apply the concept of the acute care 

IHI GTT to post-acute SNF care. OIG staff and contracted physicians 

developed the instrument in consultation with experts in trigger tool 

development, geriatricians, a geriatric pharmacist, and nurses employed in 

SNFs. The development process included reviewing triggers against 

findings of published research, clinical expertise, and two rounds of 

practice SNF record reviews. The development team used a seven-step 

modified Delphi Method to identify and refine SNF triggers (see 

Table C-1).94 The Delphi method facilitates group decision making by 

prioritizing key issues for discussion and consensus. 

Table C-1: OIG Modified Delphi Method for SNF Trigger Tool Development 

Step 

Number Step Name Step Description 

1 Facilitator Facilitator serves as a moderator throughout all rounds. 

2 Panel Convene panel of experts in the SNF setting. 

3 List Create preliminary list of SNF triggers. 

4 Survey Respond to triggers with five-point scale and comment section to 

select level of agreement that the trigger would lead to harm. 

5 Analysis Compile responses for each trigger by clustering into Agree, Neutral, 

and Disagree. A mean was calculated for each of the groups. 

6 Feedback Calculate de-identified feedback and discuss. 

7 Modifications Modify SNF trigger list according to discussion. 

Source: SNF Trigger Tool development process. 

The resulting SNF Trigger Tool worksheet includes 49 triggers that the 

nurses used to screen cases for physician review (see Table C-2). The 

worksheet divides triggers into three clinical categories: resident care, 

medication, and procedures. 

94 B.B. Brown, Delphi Process: A Methodology Used for the Elicitation of Opinions of 

Experts, RAND Corporation, September 1968. 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 40 
 

Table C-2: SNF Trigger Tool Worksheet 

Care Module Triggers Medication Module Triggers 

C1 Acute mental status change M1 Abnormal electrolytes 

C2 Aspiration M2 Abrupt medication stop 

C3 Call to physician or family members M3 Anti-emetic use 

C4 Code or Emergency Medical Services (EMS) M4 Diphenhydramine (Benadryl) use 

C5 Death M5 Elevated INR 

C6 Drop in hemoglobin/hematocrit M6 Epinephrine use 

C7 Studies for emboli: PE or DVT M7 Glucose <50, Glucagon or Dextrose supplement 

C8 Fall M8 Abrupt onset hypotension 

C9 Family complaint M9 Naloxone (Narcan) use 

C10 Any infection M10 Sodium Polystyrene (Kayexalate administration) 

C11 New or increased diuretics M11 Abnormal drug levels 

C12 High or low body temperature M12 Thrombocytopenia 

C13 In (SNF) stroke or TIA M13 Total WBC < 3000 

C14 New onset of incontinence M14 Vitamin K administration (Aqua-Mephyton) 

C15 Insertion or use of urinary catheter M15 Antibiotics started in SNF 

C16 Significant Change in Status Assessment 

in MDS (SCSA) 

M16 Increasing pain medication needs 

C17 Resident incident or accident M17 Administration of parenteral fluid 

C18 Pressure ulcer M18 Rising ALT/AST liver function test 

C19 ED visit M19 Medication-Other 

C20 Transfer to acute care hospital or observation 

(OBS) unit Procedure Module Triggers 

C21 Restraint use 

C22 Rising serum creatinine P1 Postoperative/post-procedure complication 

C23 Urinary retention P2 Procedure reintubation/BiPAP/new CPAP 

C24 New onset diarrhea P3 Procedure-Other 

C25 Prolonged constipation -- --

C26 Diagnostic radiology or imaging studies -- --

C27 Care-Other -- --

Source: OIG, Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 41 
 

 

 1 

 2 

 3 

 4 

 5 

 6 

 7 

 8 

9 

 10 

 11 

 12 

 

APPENDIX D 

Estimates, Confidence Intervals, and Key Statistics 

Table D-1: Beneficiary Level Estimates, Confidence Intervals, and Key Statistics 

Sample 

Size (n) Percentage 

95-Percent 

Confidence 

Interval 

Frequency 

95-Percent 

Confidence 

Interval 

Lower 

Bound 

Upper 

Bound 

Lower 

Bound 

Upper 

Bound 

Event Experiences for All Beneficiaries 

Experienced at least one adverse event 653 21.7% 18.3% 25.4% 21,777 18,213 25,342 

Experienced at least two adverse 

events 653 2.6% 1.6% 4.1% 2,615 1,407 3,824 

Experienced at least one temporary 

harm event and didn’t experience an 

adverse event 

653 10.7% 8.3% 13.7% 10,742 8,073 13,410 

Experienced at least one adverse event 

or at least one temporary harm event 653 32.4% 28.7% 36.2% 32,519 28,746 36,292 

Experienced only preventable adverse 

events 653 15.4% 12.4% 19.0% 15,483 12,212 18,755 

Experienced only preventable 

temporary harm events and no adverse 

events 

653 4.9% 3.5% 6.8% 4,923 3,317 6,530 

Experienced adverse events that 

contributed to death 653 1.5% 0.8% 2.8% 1,538 598 2,479 

Experienced transfer to a hospital 

because of an adverse event 653 19.4% 16.1% 23.1% 19,470 15,930 23,010 

Experienced a cascade adverse event 653 4.0% 2.5% 6.2% 3,986 2,183 5,789 

Beneficiaries Who Experienced at Least One Adverse Event or One Temporary Harm Event 

Experienced at least one hospitalization 

that was the result of an adverse event 

or a temporary harm event 

191 59.9% 52.0% 67.3% 19,470 15,930 23,010 

Beneficiaries Who Experienced at Least One Adverse Event 

Experienced temporary harm in addition 

to adverse events 127 21.2% 15.0% 29.1% 4,615 3,053 6,178 

Beneficiaries Who Experienced Temporary Harm Events and No Adverse Events 

Experienced multiple temporary harm 

events and no adverse events 64 20.1% 12.0% 31.6% 2,154 1,050 3,257 

Source: OIG analysis of SNF stays and Medicare claims for 653 Medicare beneficiaries discharged in August 2011. 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 42 
 

 

 13 

 14 

 15 

 16 

 17 

 18 

 19 

 20 

 21 

 22 

 23 

24 

 

25 

 27 

 26 

 28 

 29 

 30 

 31 

 32 

 33 

 34 

 35 

 36 

 37 

 38 

 

Table D-2: Estimates, Confidence Intervals, and Key Statistics 

Sample 

Size (n) Percentage 

95-Percent 

Confidence 

Interval 

Lower 

Bound 

Upper 

Bound 

OIG’s Modified NCC MERP Index for Categorizing Adverse Events by Level of Harm 

Harm F 148 78.5% 70.8% 86.3% 

Harm G* 148 -- -- --

Harm H 148 13.5% 6.6% 20.4% 

Harm I 148 6.2% 2.4% 9.9% 

Clinical Category for All Adverse Events 

Medication adverse events 148 37.4% 28.0% 46.8% 

Resident care adverse events 148 36.8% 27.6% 46.0% 

Infection adverse events 148 25.8% 18.0% 33.6% 

Adverse Events Related to Medication 

Delirium or other change in mental status, e.g., over-sedation 148 11.6% 4.2% 18.9% 

Excessive bleeding 148 4.9% 1.2% 8.7% 

Fall or other trauma with injury 148 3.7% 0.8% 6.6% 

Constipation, obstipation, and ileus 148 3.7% 0.8% 6.6% 

Other medication-related adverse events 148 13.5% 7.1% 20.0% 

Adverse Events Related to Resident Care 

Fall or other trauma with injury related to resident care 148 5.5% 2.0% 9.1% 

Exacerbations of preexisting conditions resulting from an omission 

of care 148 5.5% 0.3% 10.7% 

Acute kidney injury or insufficiency secondary to fluid maintenance 148 4.9% 1.2% 8.7% 

Fluid and other electrolyte disorders (e.g., inadequate management 

of fluid) 148 3.7% 0.8% 6.6% 

Venous thromboembolism, DVT, or PE related to resident 

monitoring 148 3.7% 0.3% 7.0% 

Other resident care events 148 13.5% 6.8% 20.1% 

Adverse Events Related to Infections 

Aspiration pneumonia and other respiratory infections 148 9.8% 3.8% 15.8% 

SSI associated with wound care 148 4.9% 1.6% 8.3% 

CAUTI 148 3.1% 0.4% 5.7% 

Clostridium difficile infection 148 3.1% 0.4% 5.7% 

Other infection-related adverse events 148 4.9% 1.5% 8.3% 

Clinical Category for All Temporary Harm Events 

Medication temporary harm events 113 42.8% 33.5% 52.2% 

Resident care temporary harm events 113 40.3% 30.9% 49.7% 

Infection temporary harm events 113 16.8% 10.0% 23.7% 

Continued on next page. 

*We are unable to reliably project the weighted point estimate for adverse events classified as G Level harm because of the small number of 

sample occurrences. 

Source: OIG analysis of SNF stays and Medicare claims for 653 Medicare beneficiaries discharged in August 2011. 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 43 
 

 39 

 40 

 41 

 42 

 43 

44 

 45 

 46 

 47 

 48 

 50 

 51 

 52 

53 

54 

55 

56 

57 

58 

59 

60 

61 

62 

63 

64 

65 

66 

 

Table D-2: Estimates, Confidence Intervals, and Key Statistics (Continued) 

Sample 

Size (n) Percentage 

95-Percent 

Confidence 

Interval 

Lower 

Bound 

Upper 

Bound 

Temporary Harm Events Related to Medication 

Hypoglycemic episodes (e.g., low or significant drop in blood 

glucose) 113 16.0% 9.3% 22.7% 

Fall or other trauma with injury associated with medication 113 9.2% 1.9% 16.5% 

Medication-induced delirium or other change in mental status 113 6.7% 2.3% 11.1% 

Thrush and other nonsurgical infections related to medication 113 4.2% 0.6% 7.8% 

Allergic reactions to medications (e.g., rash, itching) 113 3.4% 0.1% 6.7% 

Other temporary harm events related to medication 113 3.4% 0.1% 6.6% 

Temporary Harm Events Related to Resident Care 

Pressure ulcers 113 19.3% 10.8% 27.8% 

Fall or other trauma with injury associated with resident care 113 8.4% 3.4% 13.5% 

Skin tear, abrasion, or breakdown 113 6.7% 2.2% 11.3% 

Other resident care events 113 5.9% 1.7% 10.1% 

Temporary Harm Events Related to Infections 

CAUTI 113 5.0% 1.1% 9.0% 

SSI associated with wound care 113 5.0% 1.1% 9.0% 

Other temporary harm events related to infections 113 6.7% 1.8% 11.7% 

Preventability Classification for All Adverse Events and Temporary Harm Events 

 Preventable events 261 59.2% 52.7% 65.8% 

o Clearly preventable events 261 13.1% 8.2% 18.0% 

o Likely preventable events 261 46.1% 39.4% 52.8% 

 Not preventable events 261 36.5% 30.2% 42.8% 

o Clearly not preventable events 261 11.0% 7.3% 14.7% 

o Likely not preventable events 261 25.5% 19.7% 31.3% 

 Unable to determine 261 4.2% 0.9% 7.5% 

Preventability Classification for Adverse Events 

 Preventable adverse events 148 68.7% 60.7% 76.6% 

o Clearly preventable adverse events 148 18.3% 10.7% 26.0% 

o Likely preventable adverse events 148 50.3% 41.5% 59.2% 

 Not preventable adverse events 148 28.9% 21.1% 36.6% 

o Clearly not preventable adverse events 148 10.5% 5.5% 15.4% 

o Likely not preventable adverse events 148 18.4% 11.4% 25.4% 

 Unable to determine adverse events 148 2.5% 0.05% 4.9% 

Continued on next page. 

Source: OIG analysis of SNF stays and Medicare claims for 653 Medicare beneficiaries discharged in August 2011. 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 44 
 

67 

68 

69 

70 

71 

72 

73 

 75 

 74 

 76 

77 

78 

79 

 80 

81 

 82 

83 

 84 

 85 

86 

87 

Table D-2: Estimates, Confidence Intervals, and Key Statistics (Continued) 

Sample 

Size (n) Percentage 

95-Percent 

Confidence 

Interval 

Lower 

Bound 

Upper 

Bound 

Preventability Classification for Temporary Harm Events 

 Preventable temporary harm events 113 46.3% 36.3% 56.3% 

o Clearly preventable temporary harm events 113 5.9% 1.7% 10.1% 

o Likely preventable temporary harm events 113 40.4% 30.5% 50.3% 

 Not preventable temporary harm events 113 47.1% 36.9% 57.2% 

o Clearly not preventable temporary harm events 113 11.8% 6.0% 17.6% 

o Likely not preventable temporary harm events 113 35.3% 25.3% 45.3% 

 Unable to determine temporary harm events* 113 -- -- --

Preventable Adverse and Temporary Harm Events Within Each Clinical Category 

Medication adverse and temporary harm events 103 66.1% 56.0% 76.1% 

Resident care adverse and temporary harm events 99 56.5% 46.0% 66.9% 

Infection adverse and temporary harm events 59 51.7% 37.6% 65.7% 

Physician Rationale for All Preventable Events 

Appropriate treatment was provided in a substandard way 155 55.7% 46.9% 64.5% 

Resident’s progress was not adequately monitored 155 36.5% 28.2% 44.8% 

Necessary treatments were not provided 155 24.5% 16.5% 32.4% 

Error related to medical judgment, skill, or resident management 

occurred 155 14.3% 8.1% 20.6% 

Resident care plan was inadequate 155 11.3% 5.4% 17.3% 

Care plan was incomplete or not sufficient in describing resident 

condition or care 155 7.2% 3.3% 11.1% 

Resident’s health status was not adequately assessed 155 4.2% 1.2% 7.2% 

Physician Rationale for All Not Preventable Events 

Resident was highly susceptible to event because of health status 97 59.2% 48.0% 70.5% 

Event occurred despite proper assessment and procedures 

followed 97 31.9% 21.1% 42.8% 

Resident’s diagnosis was unusual or complex, making care difficult 97 27.1% 16.5% 37.8% 

Care provider could not have anticipated event given information 

available 97 20.4% 12.2% 28.6% 

*We are unable to reliably project the weighted point estimate for adverse events classified as G Level harm because of the small number of 

sample occurrences. 

Source: OIG analysis of SNF stays and Medicare claims for 653 Medicare beneficiaries discharged in August 2011. 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 45 
 

 

 90 

91 

 92 

93 

88

 89

Table D-3: Point Estimates and Confidence Intervals for Total and Average Additional 

Medicare Costs Associated With Adverse Events 

Estimate Description 

Sample 

Size (n) Total Cost 

95-Percent 

Confidence 

Interval 

Lower 

Bound 

Upper 

Bound 

Costs Associated With Adverse Events in SNFs 

Increased cost because of hospitalizations from adverse events that 

occurred during SNF stay 148 $207,979,213 $150,589,933 $265,368,492 

Costs Associated With Preventable Adverse Events in SNFs 

Increased cost because of hospitalizations from preventable adverse 

events that occurred during SNF stay 100 $135,548,133 $84,361,921 $186,734,346 

Source: OIG analysis of SNF stays and Medicare claims for 653 Medicare beneficiaries discharged in August 2011. 

Table D-4: Projections and Confidence Intervals for Total and Average Additional 

Medicare Costs Associated With Adverse Events Within the Clinical Categories 

Category of 

Adverse 

Events Frequency 

95-Percent 

Confidence 

Interval 

Total Cost 

95-Percent 

Confidence 

Interval 

Mean 

Cost 

95-Percent 

Confidence 

Interval 

Lower 

Bound 

Upper 

Bound 

Lower 

Bound 

Upper 

Bound 

Lower 

Bound 

Upper 

Bound 

Hospitalizations 

and costs 

associated with 

medication 

events 

7,203 4,716 9,691 $57,729,935 $29,686,945 $85,772,925 $8,372 $5,418 $11,326 

Hospitalizations 

and costs 

associated with 

resident care 

events 

7,511 4,998 10,024 $67,350,098 $39,029,148 $95,671,047 $8,967 $7,064 $10,870 

Hospitalizations 

and costs 

associated with 

infections 

5,679 3,621 7,736 $82,899,180 $38,018,755 $127,779,605 $14,599 $9,386 $19,811 

Hospitalizations 

and costs 

associated with 

all events in 

SNFs 

20,393 16,688 24,097 $207,979,213 $150,589,933 $265,368,492 $10,276 $8,241 $12,312 

Source: OIG analysis of SNF stays and Medicare claims for 653 Medicare beneficiaries discharged in August 2011. 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 46 
 

APPENDIX E 

Rates of Adverse Events and Temporary Harm Events in SNFs 

by Resident Days and SNF Admissions 

Health care facilities, particularly hospitals, commonly measure adverse 

events by incidence density, which takes into account the period during 

which residents are observed. For example, incidence density is often 

used in measuring hospital-acquired infections because risk can increase 

with the length of exposure to the health care environment.95 IHI, a 

nonprofit advisory group to hospitals, cites advantages to using incidence 

density metrics over standard incidence rates that measure the number of 

events per resident.96 IHI reports that measuring total events by resident 

days or hospital admissions enables hospitals to count multiple events 

experienced by the same beneficiary. 

The sample of 653 Medicare beneficiaries discharged during August 2011 

included 692 total SNF stays (admissions) and a total of 10,759 days in the 

SNF (resident days). We calculated resident days by subtracting the 

admission date for each SNF stay from its discharge date. Table E-1 

provides ratios for adverse events and temporary harm events in the 

sample per 1,000 resident days and per 100 admissions. 

Table E-1: Rates of Adverse and Temporary Harm Events in the Sample by 

Resident Days and SNF Admissions 

Category Per 1,000 

Resident Days 

Per 100 

Admissions 

Adverse events 14 21 

Temporary harm events 11 16 

Adverse and temporary harm events combined 24 38 

Source: OIG analysis of SNF stays for 653 Medicare beneficiaries discharged in August 2011. 

95 K.M. Arias, Outbreak Investigation, Prevention, and Control in Health Care Settings, 

Second Edition, 2009, Jones and Bartlett Publishers, pp. 330–331. 96 IHI, IHI Global Trigger Tool for Measuring Adverse Events, Second Edition, 2009, 

p. 13. 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 47 
 

 

196 

67 

106 

142 

143 

190 

1239 

60 

199 

1241 

1242 

1245 

1250 

 

 

APPENDIX F 

Adverse Events and Temporary Harm Events 

Tables F-1 and F-2 contain information about adverse events and 

temporary harm events identified in the sample, including description, 

harm level, and preventability. Table F-1 contains information about 

adverse events (148 adverse events).97 Table F-2 contains information 

about temporary harm events (113 events). 

Table F-1: Adverse Events by Clinical Category, Harm Level, and Preventability (n=148) 

Adverse Event Harm 

Level Preventability 

Events Related to Medication (55) 

Medication-induced delirium or other change in mental status (13) 

1. Delirium and agitation secondary to psychotropic and pain medications resulting in 

hospitalization F CNP 

2. Delirium, hallucinations, and respiratory failure secondary to pain and anti-anxiety medications 

(opioids and benzodiazepines) resulting in hospitalization F CP 

3. Confusion, delusions, and continuing episodes of disorientation secondary to pain medication 

(opioids and benzodiazepines) resulting in hospitalization F LNP 

4. Delirium, disorientation, and hallucinations secondary to inappropriately prescribed anti-anxiety 

medication (lorazepam) and other medications (acetaminophen and hydrocodone, 

cyclobenzaprine Hcl) 

F LP 

5. Cascade in which disorientation and hallucinations due to multiple medications 

(acetaminophen, hydrocodone, cyclobenzaprine Hcl, and lorazepam) led to a fall with resultant 

skin tear and rib fracture, which led to pneumonia resulting in hospitalization 

F CP 

6. Acute change in mental status due to inadequate hydration therapy that was exacerbated by 

multiple medications F CP 

7. Acute change in mental status secondary to medication F LNP 

8. Cascade event in which confusion and somnolence secondary to medications led to 

dehydration because of decreased fluid intake F LP 

9. Delirium secondary to multiple pain medications (opioids) resulting in hospitalization F LP 

10. Delirium secondary to psychiatric medications (hydrocodone) F LP 

11. Confusion secondary to beta blocker (metoprolol) with sinus bradycardia F LP 

12. Episode of unresponsiveness secondary to psychiatric medication (lithium)* F CP 

13. Lethargy and altered mental status secondary to medication* F LP 

*Event identified during screener false-negative rate review. 

Continued on next page. 

97 The harm level is classified according to the modified version of the NCC MERP 

Index for Categorizing Errors (E–I). Preventability determination is reflective of the 

physician review index: CP = clearly preventable, LP = likely preventable, LNP = likely 

not preventable, CNP = clearly not preventable, and UTD = unable to determine. 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 48 
 

9 

16 

38 

50 

90 

92 

127 

194 

95 

115 

146 

164 

1206 

1210 

89 

126 

1207 

1223 

1240 

2001 

93 

94 

111 

213 

1232 

 

Table F-1: Adverse Events by Clinical Category, Harm Level, and Preventability (n=148) 

(Continued) 

Adverse Event Harm 

Level Preventability 

Events Related to Medication (55) (continued) 

Excessive bleeding due to medication (8) 

1. Cascade event in which hematemesis (gastrointestinal bleeding) from an anticoagulant 

(warfarin) led to aspiration, which resulted in death I LP 

2. Epistaxis (significant bleeding through nose) due to anticoagulant (warfarin) resulting in 

hospitalization H CP 

3. Gastrointestinal bleeding due to anticoagulation treatment (aspirin) resulting in hospitalization F LNP 

4. Cascade event in which hemoptysis (coughing up blood) associated with anticoagulant led to 

aspiration, cardiac arrest, anoxic encephalopathy and contributed to resident’s death I LNP 

5. Cascade event in which anticoagulant (warfarin) toxicity led to hematemesis (gastrointestinal 

bleeding) with resultant hypotension and kidney insufficiency resulting in hospitalization H LNP 

6. Coumadin toxicity led to gastrointestinal bleeding resulting in hospitalization F LP 

7. Anticoagulant overdose led to hematemesis and subdural hematoma H CP 

8. Gastrointestinal bleeding secondary to anticoagulants resulting in hospitalization F CNP 

Fall or other trauma with injury secondary to the effects of medication (6) 

1. Fall associated with atypical antipsychotic (quetiapine) led to right hip fracture resulting in 

hospitalization G LNP 

2. Fall associated with inappropriately prescribed atypical antipsychotic (quetiapine) resulting in 

femur fracture resulting in hospitalization F LP 

3. Fall associated with appropriately prescribed antipsychotic medication (haloperidol decanoate) 

resulting in injury to hand F CNP 

4. Fall associated with appropriately prescribed atypical antipsychotic (olanzapine) and 

antidepressant (escitalopram) that caused a hip fracture resulting in hospitalization F LNP 

5. Fall associated with inappropriately prescribed opiates for pain (hydromorphone, 

hydrocodone/APAP, tramadol) resulting in rib fracture F LP 

6. Fall associated with inappropriately prescribed antipsychotics (haloperidol decanoate and 

risperidone) resulting in hematoma F LP 

Constipation, obstipation, and ileus related to medication (6) 

1. Inadequate bowel care led to significant constipation secondary to opiates resulting in 

hospitalization F LP 

2. Severe constipation due to pain medications (opioids) F LP 

3. Significant ileus secondary to narcotics resulting in hospitalization F CNP 

4. Significant constipation secondary to opiates resulting in hospitalization F LNP 

5. Significant ileus secondary to opiates and inadequate bowel care resulting in hospitalization F LP 

6. Abdominal distention with ileus secondary to opiates F LP 

Hypoglycemic events related to medication (5) 

1. Hypoglycemic episode characterized by blood glucose of 31 H LP 

2. Hypoglycemic episode characterized by blood glucose of 34 H LP 

3. Hypoglycemic episode characterized by blood glucose of 32 H LP 

4. Hypoglycemic episode characterized by blood glucose of 38 resulting in hospitalization and 

contributing to the resident's death I LP 

5. Hypoglycemic episode characterized by a blood glucose of 20 resulting in hospitalization and 

contributing to the resident's death I LP 

Continued on next page. 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 49 
 

12 

134 

145 

147 

98 

100 

151 

107 

1209 

51 

123 

133 

184 

119 

6 

47 

78 

10 

24 

33 

72 

75 

155 

159 

215 

1215 

Table F-1: Adverse Events by Clinical Category, Harm Level, and Preventability (n=148) 

(Continued) 

Adverse Event Harm 

Level Preventability 

Events Related to Medication (55) (continued) 

Medication-induced allergic reaction (4) 

1. Cascade event in which antibiotics (levofloxacin) given for an infected incision site caused an 

unanticipated allergic reaction characterized by pruritic rash over most of resident's body F CNP 

2. Rash secondary to anticoagulant F CNP 

3. Rash secondary to antibiotic F CNP 

4. Rash secondary to antibiotics F CNP 

Ketoacidosis, hyperosmolar coma, and other complications of diabetes related to insulin management (3) 

1. Failure to provide adequate insulin care led to diabetic ketoacidosis resulting in hospitalization F CP 

2. Cascade event in which hyperosmolar diabetic coma characterized by somnolence and 

vomiting led to aspiration resulting in hospitalization and contributing to the resident’s death I CNP 

3. Diabetic ketoacidosis due to insufficient administration of insulin resulting in hospitalization F LP 

Anemia and other blood count problems secondary to medication (2) 

1. Cascade event in which provision of antibiotics led to pancytopenia, angina, and pneumonia 

resulting in hospitalization F LP 

2. Anemia due to inadequate administration of epoetin alfa (anemia medication) in resident with 

chronic kidney failure resulting in hospitalization F LP 

Hypotension secondary to medication (2) 

1. Syncope with atrial fibrillation and hypotension secondary to overdose of levothyroxine and 

liothyronine resulting in hospitalization F LP 

2. Hypotension secondary to ACE inhibitor resulting in hospitalization F LP 

Nausea and vomiting secondary to medication (2) 

1. Digoxin toxicity led to nausea F LP 

2. Nausea and vomiting secondary to antibiotic F LP 

Other medication events (4) 

1. Acute kidney injury due to inadequate diuretic therapy characterized by hyperkalemia resulting 

in hospitalization H LP 

2. Stroke because of a failure to provide anticoagulants resulting in hospitalization G LP 

3. Hyperkalemia and severe dehydration due to ACE inhibitor (lisinopril) resulting in hospitalization H CP 

4. Seizure secondary to inadequate monitoring of antiepileptic medication resulting in 

hospitalization F CP 

Events Related to Resident Care (54) 

Fall or other trauma with injury related to resident care (9) 

1. Fall resulting in chest hematoma F LP 

2. Fall with injury resulting in hospitalization F LNP 

3. Fall with large hematoma on head resulting in hospitalization F LP 

4. Fall with nasal fracture resulting in hospitalization F LNP 

5. Fall with injury resulting in hospitalization F LNP 

6. Fall resulting in effusion and hematoma on knee resulting in hospitalization F LNP 

7. Fall resulting in multiple skin tears F LP 

8. Fall resulting in hematoma on head resulting in hospitalization F LNP 

9. Ankle fracture due to unwitnessed trauma in SNF F UTD 

Continued on next page. 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 50 
 

5 

87 

101 

109 

112 

114 

165 

256 

 

58 

76 

83 

118 

1229 

1231 

36 

43 

183 

185 

212 

234 

Table F-1: Adverse Events by Clinical Category, Harm Level, and Preventability (n=148) 

(Continued) 

Adverse Event Harm 

Level Preventability 

Events Related to Resident Care (54) (continued) 

Dehydration and related electrolyte disorders associated with resident care (8) 

1. Cascade event in which substandard monitoring of resident with known obstructive kidney 

disease resulted in progressive kidney failure, hyperkalemia (electrolyte abnormality 

characterized by high potassium), and cardiac arrest, which contributed to the resident’s death 

I CP 

2. Cascade event in which failure to adequately hydrate resident with dysphagia led to 

hypovolemia, hypernatremia (electrolyte abnormality characterized by high sodium), 

hypotension, paroxysmal atrial tachycardia, need for cardioversion, non-STEMI myocardial 

infarction, and acute kidney injury resulting in hospitalization 

H CP 

3. Cascade event in which failure to recognize postoperative delirium led to poor oral intake, 

hyperkalemia, and hypernatremia resulting in hospitalization F LP 

4. Severe hypernatremia due to inadequate hydration resulting in hospitalization F LNP 

5. Hyponatremia with increased lethargy and change in mental status due to free-water 

gastrostomy tube flushes resulting in hospitalization F LP 

6. Change in mental status due to electrolyte disorder caused by multiple free water gastrostomy 

tube flushes in a resident with a recent history of syndrome of inappropriate antidiuretic 

hormone secretion (SIADH) 

F LP 

7. Cascade event in which insufficient monitoring of ileostomy led to leaking, excoriation around 

insertion site, significant dehydration, acute kidney injury, and high potassium H LP 

8. Significant dehydration due to inadequate hydration resulting in hospitalization F LP 

Acute kidney injury or insufficiency secondary to fluid maintenance (6) 

1. Cascade in which acute kidney injury due to inadequate hydration led to high potassium and 

uremia characterized by significant lethargy resulting in hospitalization F LP 

2. Acute kidney injury characterized by severe hyperkalemia due to inadequate monitoring of 

electrolytes and serum creatinine resulting in hospitalization H LP 

3. Acute kidney insufficiency and confusion due to inadequate hydration therapy resulting in 

hospitalization F LP 

4. Acute kidney injury due to poor monitoring of hydration and inadequate diuretic therapy 

complicated by antipsychotics used to treat associated delirium F LP 

5. Cascade event in which inadequate hydration led to acute kidney insufficiency, hypotension, 

and obtundation F LP 

6. Acute kidney injury due to progressive dehydration resulting in hospitalization and contributing 

to the resident’s death I LP 

Venous thromboembolism, DVT, or PE related to resident monitoring (6) 

1. DVT due to insufficient DVT prophylaxis resulting in hospitalization and a PE that contributed to 

the resident’s death I UTD 

2. PE due to inadequate resident monitoring that resulted in a hospitalization and contributed to 

the resident’s death I CP 

3. Delay in recognition of pneumothorax resulting in hospitalization F LP 

4. DVT and pulmonary embolism due to inadequate monitoring resulting in hospitalization F CNP 

5. DVT due to a failure to provide adequate DVT monitoring and prophylaxis resulting in 

hospitalization F LP 

6. Significant DVT due to failure to provide sufficient DVT monitoring and prophylaxis resulting in 

hospitalization F LNP 

Continued on next page. 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 51 
 

161

170

214

227

240

1244

19 

136

246

1243

68 

160

205

20 

77 

31 

249

59 

254

203

55 

 1228

 61 

73 

166

Table F-1: Adverse Events by Clinical Category, Harm Level, and Preventability (n=148) 

(Continued) 

Adverse Event Harm 

Level Preventability 

Events Related to Resident Care (54) (continued) 

Exacerbations of preexisting conditions resulting from an omission of care (6) 

1. Suicide attempt by resident at risk for suicide characterized by self-inflicted cuts on wrists 

resulting in hospitalization due to inadequate compliance with a care plan that was not sufficient 

for the resident 

F LP 

2. Failure to properly assess resident in SNF and in preceding hospital stay, which led to delay in 

recognizing hip fracture resulting in hospitalization F CP 

3. Jaundice, low hemoglobin, and lethargy due to a delay in recognition of acquired autoimmune 

hemolytic anemia resulting in hospitalization F CNP 

4. Hydronephrosis due to delay in needed post-hospital followup care for resident with significant 

urinary tract obstruction F LP 

5. Failure to provide appropriate intervention for increasing hypothyroidism and monitoring of 

increasing heart failure, which led to episode of exacerbated heart failure resulting in 

hospitalization 

F LP 

6. Reduction in diuretics and failure to adequately monitor increased weight gain (anasarca) 

associated with congestive heart failure and cirrhosis resulting in hospitalization and contributing 

to the resident’s death* 

H LP 

Respiratory issues (other than infections below) (4) 

1. Hypoxia and respiratory distress due to insufficient pulmonary suction resulting in hospitalization H CP 

2. Delay in diagnosis of pneumothorax and inadequate monitoring, which led to significant 

worsening of condition characterized by difficulty breathing resulting in hospitalization H LP 

3. Failure to provide adequate tracheostomy care resulted in acute respiratory failure H LNP 

4. Cascade event in which delay in treatment for pleural effusion led to worsening of hypoxia 

(inadequate oxygen in blood) resulting in hospitalization for chest tube, drainage, and intubation* F CP 

Excessive bleeding related to resident care (3) 

1. Excessive bleeding from infection site resulting in hospitalization F LP 

2. Excessive bleeding around wound vacuum pump site resulting in hospitalization F LNP 

3. Hematuria secondary to Foley catheter resulting in hospitalization F UTD 

Displacement of feeding tubes related to resident monitoring (2) 

1. Feeding tube displacement due to lack of monitoring resulting in hospitalization F LP 

2. Feeding tube displacement due to lack of monitoring resulting in hospitalization F LP 

Hypotension related to resident care (2) 

1. Cascade event in which dehydration due to inadequate monitoring led to hypotension, sinus 

tachycardia, and atrial fibrillation resulting in hospitalization F LP 

2. Hypotension and hematuria due to inadequate monitoring of Foley catheter resulting in 

hospitalization F CP 

Stage III or IV pressure ulcers (2) 

1. Stage III pressure ulcer on sacrum and stage II pressure ulcer on buttocks F CP 

2. Stage III pressure ulcer on heel G LP 

Other resident care events (6) 

1. Clogged arteriovenous shunt (dialysis access device) due to excessive blood clotting F LP 

2. Significant constipation resulting in hospitalization F LNP 

3. Cascade event in which failure to provide adequate skin care caused a skin friction abrasion that 

progressed to a stage II pressure ulcer and developed cellulitis resulting in hospitalization F LP 

4. Omission of care, which led to progressive weakness and decreased bowel and overall functional 

status resulting in hospitalization F CP 

5. Substandard urinary catheter care, which led to urinary retention resulting in hospitalization F LP 

6. Cascade event in which pulmonary fluid overload led to decreased oxygenation, respiratory 

failure, atrial flutter, and significant lethargy resulting in hospitalization H LP 

*Event identified during screener false-negative rate review.
 

Continued on next page. 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 52 
 

22

71

84

116

135

188

207

210

220

1224

1234

1236

1254

4 

11 

45 

53 

54 

149

150

217

99 

 187

216

 255

 1225

74 

158

218

229

242

Table F-1: Adverse Events by Clinical Category, Harm Level, and Preventability (n=148) 

(Continued) 

Adverse Event Harm 

Level Preventability 

Events Related to Infections (39) 

Aspiration pneumonia and other respiratory infections (13) 

1. Aspiration pneumonia due to inadequate aspiration precautions and monitoring of resident 

with history of dysphagia F CNP 

2. Aspiration pneumonia due to failure to monitor resulting in hospitalization F LP 

3. Cascade event in which dysphagia and vomiting led to aspiration pneumonia, associated with 

hyperglycemia (with diabetic ketoacidosis or hyperosmolar coma) and hyponatremia, resulting 

in hospitalization 

F CNP 

4. Several episodes of emesis, which led to aspiration pneumonia resulting in hospitalization F CNP 

5. Aspiration pneumonia resulting in hospitalization F LP 

6. Aspiration pneumonia resulting in hospitalization F LNP 

7. Cascade event in which aspiration pneumonitis led to respiratory failure resulting in 

hospitalization H LP 

8. Aspiration pneumonitis resulting in hospitalization F CNP 

9. Aspiration pneumonia characterized by tachypnea, dyspnea, and chest congestion resulting in 

hospitalization and contributing to the resident’s death I CNP 

10. Emesis associated with lung infiltrate resulting in hospitalization F CNP 

11. Recurrence of pneumonia due to incomplete treatment of prior pneumonia resulting in 

hospitalization F UTD 

12. Cascade event in which aspiration pneumonitis led to respiratory failure, which exacerbated 

resident’s COPD resulting in hospitalization for needed BIPAP treatment H CP 

13. Aspiration pneumonia resulting in hospitalization* F LNP 

SSI attributable to wound care (8) 

1. Superficial infection around surgical incision site on lower back F LP 

2. Superficial infection around surgical incision site for recent knee arthroplasty F LP 

3. Superficial infection around surgical incision site on hip F LP 

4. Superficial infection around surgical incision site on leg resulting in hospitalization F LP 

5. Superficial infection around surgical incision site for recent toe resection resulting in 

hospitalization F LP 

6. Cellulitis at surgical site resulting in hospitalization F LP 

7. Cellulitis at PEG tube placement site resulting in hospitalization F LNP 

8. Cellulitis at site of skin graft resulting in hospitalization F LNP 

CAUTI (5) 

1. Urinary tract infection associated with urinary catheter resulting in hospitalization F LP 

2. Cascade in which a partial obstruction due to Foley catheter placement led to a urinary tract 

infection. F LP 

3. Urinary tract infection associated with urinary catheter F LP 

4. Urinary tract infection associated with urinary catheter characterized by acute change in 

mental status resulting in hospitalization F CP 

5. Cascade event in which urosepsis led to dehydration, hypotension and paroxysmal 

supraventricular tachycardia F LNP 

Clostridium difficile infection (5) 

1. Clostridium difficile infection resulting in hospitalization F LP 

2. Clostridium difficile infection F LP 

3. Clostridium difficile infection associated with significant weight loss resulting in hospitalization F CP 

4. Clostridium difficile infection resulting in hospitalization F LNP 

5. Clostridium difficile infection resulting in hospitalization F LP 

*Event identified during screener false-negative rate review.
 

Continued on next page. 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 53 
 

39

88

167

86

182

243

69 

140

Table F-1: Adverse Events by Clinical Category, Harm Level, and Preventability (n=148) 

Adverse Event (Continued) Harm 

Level Preventability 

Events Related to Infections (39) (continued) 

Sepsis (3) 

1. Urinary tract infection associated with urinary catheter characterized by acute change in 

mental status and somnolence resulting in hospitalization F CP 

2. Sepsis due to progression of inadequately treated pneumonia resulting in hospitalization H CP 

3. Failure to provide adequate care for urinary tract infection, which led to sepsis resulting in 

hospitalization F LNP 

Vascular-catheter associated infection, e.g., PICC line, central line (3) 

1. Port site infection resulting in hospitalization F LP 

2. Infection (MRSA) around dialysis insertion site resulting in hospitalization F LNP 

3. Cascade event involving DVT and catheter-associated central line infection F LP 

Soft tissue or other nonsurgical infection (2) 

1. Cellulitis on legs resulting in hospitalization F LNP 

2. Progressive infection characterized by rash, sloughing, and necrosis resulting in 

hospitalization F CP 

Source: OIG analysis of SNF stays for 653 Medicare beneficiaries discharged in August 2011. 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 54 
 

224 

25 

34 

70 

82 

91 

96 

125 

148 

153 

163 

171 

173 

244 

245 

15 

252 

1208 

1211 

7 

13 

17 

66 

79 

130 

178 

200 

27 

154 

157 

168 

1213 

1235 

1252 

122 

Table F-2: Temporary Harm Events by Clinical Category and Preventability (n=113) 

Temporary Harm Event Preventability 

Events Related to Medication (48) 

Hypoglycemic episodes (e.g., low or significant drop in blood glucose) (19) 

1. Multiple hypoglycemic episodes characterized by lowest blood glucose of 24 CP 

2. Hypoglycemic episode characterized by blood glucose of 32 LP 

3. Multiple hypoglycemic episodes characterized by lowest blood glucose of 35 CP 

4. Multiple hypoglycemic episodes characterized by blood glucose of 55 and unresponsiveness CP 

5. Hypoglycemic episode characterized by blood glucose of 43 LP 

6. Hypoglycemic episode characterized by blood glucose of 59 and lethargy LP 

7. Hypoglycemic episode characterized by blood glucose of 39 LNP 

8. Hypoglycemic episode characterized by blood glucose of 49 LP 

9. Hypoglycemic episode characterized by blood glucose of 49 and diaphoresis (excessive sweating) LNP 

10. Multiple hypoglycemic episodes characterized by lowest blood glucose of 66 and diaphoresis CP 

11. Hypoglycemic episode characterized by significant drop in blood glucose from baseline LP 

12. Hypoglycemic episode characterized by shaking and heart palpitations LP 

13. Hypoglycemic episode characterized by blood glucose of 48 LP 

14. Hypoglycemic episode characterized by a significant drop in blood glucose LP 

15. Cascade event in which hypoglycemic episode characterized by blood glucose of 53 resulted in fall LP 

16. Hypoglycemic episode characterized by symptoms and blood glucose of 57 CNP 

17. Multiple hypoglycemic episodes characterized by blood glucose of 54 and 48 LP 

18. Hypoglycemic episodes characterized by significant drop in blood glucose and trembling LP 

19. Multiple hypoglycemic episodes characterized by lowest blood glucose of 20 CP 

Medication-induced delirium or other change in mental status (8) 

1. Delirium secondary to pain medication (hydrocodone) LP 

2. Delirium and hallucinations due to pain medication (opioid) LP 

3. Delirium and hallucinations secondary to polypharmacy LP 

4. Delirium secondary to pain medication (opioid), which caused resident to pull IV tube LP 

5. Confusion and anxiety secondary to pain medication (oxycodone) LP 

6. Lightheadness and vertigo due to pain medication (opioids) LNP 

7. Confusion secondary to pain medication (opioids) LP 

8. Episode of diaphoresis and dizziness due to pain medication (oxycodone and paracetamol) CNP 

Fall or other trauma with injury associated with medication (8) 

1. Fall associated with inappropriately prescribed anti-anxiety medication (clonazepam) resulting in 

injury to head LP 

2. Fall associated with appropriately prescribed anti-anxiety medication (lorazepam) resulting in 

abrasions LNP 

3. Fall associated with anti-anxiety medications (lorazepam and escitalopram) and inappropriately 

prescribed atypical antipsychotropic medication (risperidone) resulting in abrasion LP 

4. Multiple falls associated with inappropriately prescribed antidepressant (fluoxetine) and anti-anxiety 

medications (selective serotonin reuptake inhibitor and lorazepam) resulting in skin tears and 

abrasions 

LP 

5. Fall associated with poor diabetes management (multiple episodes of hypoglycemia and 

hyperglycemia) resulting in abrasions LP 

6. Fall associated with inappropriately prescribed anticholinergic (amitriptyline and perphenazine) 

resulting in skin tear on forearm LP 

7. Delirium and disorientation secondary to opiates for pain (oxycodone) resulting in multiple falls 

without injury* LNP 

8. Fall associated with psychotropic medications (alprazolam and risperidone) resulting in abrasions LP 

* Event identified during screener false-negative rate review.
 

Continued on next page.
 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 55 
 

 

35 

40 

46 

49 

241 

30 

176 

186 

230 

18 

108 

121 

2 

28 

52 

63 

81 

104 

110 

124 

156 

169 

195 

209 

223 

225 

239 

250 

1226 

1248 

132

1233 

57

Table F-2: Temporary Harm Events by Clinical Category and Preventability (n=113) 

(Continued) 

Temporary Harm Event Preventability 

Events Related to Medication (48) continued 

Thrush and other nonsurgical infections related to medication (5) 

1. Oral thrush secondary to antibiotics CNP 

2. Candida vaginitis secondary to antibiotics CNP 

3. Oral and pharyngeal thrush secondary to antibiotic CNP 

4. Pharyngeal thrush secondary to antibiotic CNP 

5. Candida vaginitis and oral thrush secondary to antibiotics LNP 

Allergic reactions to medications (e.g., rash, itching) (4) 

1. Allergic reaction to medication (fluroquinolone antibiotic) characterized by itching CNP 

2. Rash in groin area due to immunosuppressant (methotrexate) LNP 

3. Skin rash on abdomen and legs associated with medication CNP 

4. Pruritus associated with narcotics CNP 

Constipation, obstipation, and ileus (2) 

1. Significant constipation secondary to pain medication (opioids) LNP 

2. Significant constipation secondary to pain medication (opioids) and inadequate bowel care LP 

Other medication events (2) 

1. Seizure in resident with history of seizures during period of inadequate levels of anti-epileptic 

(phenytoin) LNP 

2. Significant and unanticipated diarrhea secondary to laxative LP 

Events Related to Resident Care (45) 

Pressure ulcers (20) 

1. Stage I pressure ulcer UTD 

2. Progression of stage I pressure ulcer to stage II pressure ulcer LP 

3. Stage I pressure ulcers on heels LP 

4. Progression of stage I pressure ulcer to a stage II pressure ulcer LNP 

5. Stage I pressure ulcers on buttocks and heel LP 

6. Stage II pressure ulcer on buttocks LP 

7. Stage I pressure ulcer on coccyx LP 

8. Stage I pressure ulcer LP 

9. Stage II pressure ulcers on thigh and stage I pressure ulcers on buttock and coccyx LNP 

10. Progression of stage I pressure ulcers on coccyx and heels to stage II ulcers LNP 

11. Progression of pressure ulcer on buttocks from stage I to stage II LNP 

12. Stage I pressure ulcer on heel LNP 

13. Stage I pressure ulcer on heel LNP 

14. Progression of stage I pressure ulcer to stage II LP 

15. Multiple stage I pressure ulcers on heels, elbow, scapula, and toe CNP 

16. Stage II pressure ulcer on heel CP 

17. Stage I pressure ulcer on coccyx* UTD 

18. Unstagable pressure ulcer on left heel LNP 

19. Unstagable pressure ulcer on right heel LP 

20. Stage III pressure ulcer on hand LNP 

* Event identified during screener false-negative rate review.
 

Continued on next page.
 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 56 
 

 

1 

29 

37 

85 

198 

211 

232 

236 

247 

1230 

97 

141 

162 

179 

181 

231 

1220 

1222 

105 

80 

65 

3 

120 

14 

253 

21 

102 

113 

128 

177 

226 

Table F-2: Temporary Harm Events by Clinical Category and Preventability (n=113) 

(Continued) 

Temporary Harm Event Preventability 

Events Related to Resident Care (45) continued 

Fall or other trauma with injury associated with resident care (10) 

1. Fall resulting in skin tear LP 

2. Fall with injury to head LP 

3. Fall with skin tear LNP 

4. Trauma while in bed characterized by abrasions on temple and elbow LNP 

5. Fall resulting in abrasions on face and elbow LNP 

6. Fall resulting in elbow fracture LNP 

7. Multiple falls resulting in skin tear on hand and elbow LNP 

8. Fall resulting in multiple skin tears on appendages and bruising on head LNP 

9. Fall from motorized wheelchair resulting in multiple scrapes and abrasions CNP 

10. Fall resulting in hematoma on head LNP 

Skin tear, abrasion, or breakdown (8) 

1. Skin tears on arm and leg LNP 

2. Skin tear on leg LNP 

3. Multiple skin breakdowns above the coccyx LNP 

4. Skin tear on elbow CNP 

5. Pressure wound on leg associated with cast LP 

6. Abrasion on forearm caused by collision with railing LNP 

7. Skin tear on right forearm LNP 

8. Multiple skin excoriations UTD 

Other resident care events (7) 

1. Acute urinary retention LNP 

2. Multiple day delay in appropriate treatment of excessive swelling in a resident recovering from a hip 

fracture, which resulted in difficulty breathing LP 

3. Hypotension due to inadequate hydration therapy LP 

4. Failure to monitor resident, which led to dislodged enteral feeding tube requiring multiple 

replacement attempts LNP 

5. Cascade event in which inadequate monitoring led to severe dehydration with associated confusion 

leading to falls with minor injuries LP 

6. Blistering caused by medical tape LP 

7. Acute kidney injury secondary to inadequate monitoring of urinary retention LNP 

Events Related to Infections (20) 

CAUTI (6) 

1. Multiple catheter associated urinary tract infections secondary to multiple catheterizations. LP 

2. Recurrent urinary tract infections associated with urinary catheter LP 

3. Urinary tract infection associated with urinary catheter LP 

4. Urinary tract infection associated with urinary catheter CP 

5. Urinary tract infection associated with urinary catheter LNP 

6. Urinary tract infection associated with urinary catheter LP 

Continued on next page. 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 57 
 

 

174 

180 

206 

208 

238 

1219 

103 

129 

131 

193 

23 

228 

1246 

1212 

 

Table F-2: Temporary Harm Events by Clinical Category and Preventability (n=113) 

Temporary Harm Event Preventability 

Events Related to Infections (20) continued 

SSI attributable to wound care (6) 

1. Superficial infection at surgical incision site LNP 

2. Superficial infection at surgical incision site LNP 

3. Cellulitis at surgical site LP 

4. Cellulitis at surgical site LP 

5. Superficial infection at surgical incision site for a lower leg fracture LP 

6. Superficial infection at surgical incision site for recent knee replacement UTD 

Soft tissue or other nonsurgical infection (4) 

7. Conjunctivitis on eye LNP 

8. Fungal skin infection on abdomen LNP 

9. Blepharitis (swelling of the eyelids) LNP 

10. Bacterial conjunctivitis UTD 

Clostridium difficile infection (2) 

11. Clostridium difficile infection following treatment with broad spectrum antibiotic CNP 

12. Clostridium difficile infection LP 

Other infections (2) 

13. Sepsis resulting from urinary tract infection LNP 

14. Aspiration pneumonia CNP 

Source: OIG analysis of SNF stays for 653 Medicare beneficiaries discharged in August 2011. 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 58 
 

APPENDIX G 

Agency Comments: AHRQ 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 59
 
Also related to this recommendation, AHRQ is now working with CMS on their 11th Scope of Work 

for QIOs, and in particular we are working to resolve issues and to communicate guidance related to 

nursing home reporting of adverse events. 

We look forward to following up with yoU: regarding our activities related to the above 

recommendations, as well as to collaborating as appropriate with our colleagues at CMS. 

We believe that your previous reports on adverse events in hospitalized Medicare patients have 

provided valuable information to the public and to Federal and private-sector healthcare leaders. This 

report promises to do the same by addressing a new and especially vulnerable patient population. 

Ifyou or yout staff has any questions, please feel free to contact Dr. Bill Munier, Director, Center for 

Quality Improvement and Patient Safety at William.munier@ahrq.hhs.gov or 301-427-1921 

Richard Kronick, Ph.D. 

Attachment 

... ..... . . ... 

Adverse Events in Skilled Nursing Facilities: National incidence Among Medicare Beneficiaries (OEI-06-11-00370) 60 

I 
 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 61 
Agency Comments: CMS 

.~·~·~ (, r_ 	DEPARTMENT OF HEALTII & HUMAN SERVICES Centers lor Medicare & Medicaid Services 

5 Administrator 

Washington, DC 20201 

DATE: DEC Z 3 2013 

TO: 	 Daniel R. Levinson 

Inspector General 

FROM: 	 Ma~ l'lwenner 

Administrator 

SUBJECT: 	 Office oflnspector General (OIG) Draft Report: "Adverse Events in Skilled Nursing 

Facilities: National Incidence among Medicare Beneficiaries" (OEI-06-11-00370) 

The Centers for Medicare & Medicaid Services (CMS) appreciates the opportunity to review and 

comment on the above subject OIG draft report. This is another study in a series ofremarkable 

OIG reports on adverse events. Through a significant investment in original research generating 

new information not otherwise available, each such report has made important contributions to 

our understanding ofthe nature and prevalence of adverse events in hospitals and nursing homes. 

01G objectives for this report were to--(1) Estimate the national incidence of adverse and 

temporary harm events for Medicare beneficiaries in skilled nursing facility (SNF) post-acute 

care; (2) Assess the extent to which adverse and temporary harm events were preventable and 

identify factors contributing to these events; and (3) Estimate the costs associated with adverse 

and temporary harm events to the Medicare program. 

CMS fully concurs with OIG on the importance ofidentifying avoidable adverse events among 

nursing home residents and improving the quality oflife and care for nursing home residents. 

OIG recommendations and CMS responses to those recommendations are discussed below. 

OIG Recommendation 

The OIG recommends that AHRQ and CMS should raise awareness of adverse events in postacute care and seek to reduce harm to nursing home residents through methods used to promote 

hospital safety. 

CMS Response 

The CMS concurs with this recommendation. We agree that helping nursing homes to have a 

better understanding of adverse events and an awareness ofthe preventable events that often lead 

to resident harm could reduce preventable i~ury and harm to residents. We also agree that 

reviewing those methods for promoting hospital safety would be valuable in the development of 

nursing home information. Section 6102 (c) ofthe Affordable Care Act also established specific 

requirements for nursing homes to develop Quality Assessment and Performance Improvement 

(QAPI) activities, and required CMS to develop technical assistance materials in advance of a 

new QAPI regulation to help establish standards and distribute best practices for meeting these 

standards. CMS launched the nursing home QAPI website in summer of2013 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 62 
 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 63 
 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 64 
 

ACKNOWLEDGMENTS 

This report was prepared under the direction of Kevin K. Golladay, 

Regional Inspector General for Evaluation and Inspections in the Dallas 

regional office; Ruth Ann Dorrill, Deputy Regional Inspector General; and 

Blaine Collins, Deputy Regional Inspector General. 

Jeremy Moore served as the team leader for this study. Other principal 

Office of Evaluation and Inspections staff from the Dallas regional office 

who contributed to the report include Maria Balderas and Nathan Dong. 

Central office staff who provided support include Heather Barton, Mandy 

Waltz Brooks, Kevin Farber, Althea Hosein, Sandy Khoury, Berivan 

Demir Neubert, and Diane Reinke. 

Adverse Events in Skilled Nursing Facilities: National Incidence Among Medicare Beneficiaries (OEI-06-11-00370) 65 
 

Office of Inspector General

http://oig.hhs.gov 

The mission of the Office of Inspector General (OIG), as mandated by Public Law 95-452, as 

amended, is to protect the integrity of the Department of Health and Human Services 

(HHS) programs, as well as the health and welfare of beneficiaries served by those 

programs. This statutory mission is carried out through a nationwide network of audits, 

investigations, and inspections conducted by the following operating components: 

Office of Audit Services 

The Office of Audit Services (OAS) provides auditing services for HHS, either by conducting 

audits with its own audit resources or by overseeing audit work done by others. Audits 

examine the performance of HHS programs and/or its grantees and contractors in carrying 

out their respective responsibilities and are intended to provide independent assessments of 

HHS programs and operations. These assessments help reduce waste, abuse, and 

mismanagement and promote economy and efficiency throughout HHS. 

Office of Evaluation and Inspections 

The Office of Evaluation and Inspections (OEI) conducts national evaluations to provide 

HHS, Congress, and the public with timely, useful, and reliable information on significant 

issues. These evaluations focus on preventing fraud, waste, or abuse and promoting 

economy, efficiency, and effectiveness of departmental programs. To promote impact, OEI 

reports also present practical recommendations for improving program operations. 

Office of Investigations 

The Office of Investigations (OI) conducts criminal, civil, and administrative investigations 

of fraud and misconduct related to HHS programs, operations, and beneficiaries. With 

investigators working in all 50 States and the District of Columbia, OI utilizes its resources 

by actively coordinating with the Department of Justice and other Federal, State, and local 

law enforcement authorities. The investigative efforts of OI often lead to criminal 

convictions, administrative sanctions, and/or civil monetary penalties. 

Office of Counsel to the Inspector General 

The Office of Counsel to the Inspector General (OCIG) provides general legal services to 

OIG, rendering advice and opinions on HHS programs and operations and providing all 

legal support for OIG’s internal operations. OCIG represents OIG in all civil and 

administrative fraud and abuse cases involving HHS programs, including False Claims Act, 

program exclusion, and civil monetary penalty cases. In connection with these cases, OCIG 

also negotiates and monitors corporate integrity agreements. OCIG renders advisory 

opinions, issues compliance program guidance, publishes fraud alerts, and provides other 

guidance to the health care industry concerning the anti-kickback statute and other OIG 

enforcement authorities.