RESEARCHERS’ GUIDE TO VA DATA

1 

Assessing Inpatient and Outpatient 

VA Healthcare Use

December 2, 2013

Presented by:

Denise M. Hynes, MPH, PhD, RN

2013-2014 VIReC Database and Methods Cyber Seminar Series 
RESEARCHERS’ GUIDE TO VA DATA

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Audience Question

What particular aspects of 

healthcare use are you interested in 

measuring? 
RESEARCHERS’ GUIDE TO VA DATA

Topics for Today

How has healthcare utilization been 

measured in VA studies?

Overview of Medical SAS datasets

Finding information in the Medical 

SAS datasets

Examples of VA studies that have 

assessed healthcare use

Where to go for more help

3 
RESEARCHERS’ GUIDE TO VA DATA

Topics for Today

How has healthcare utilization been 

measured in VA studies?

Overview of Medical SAS datasets

Finding information in the Medical 

SAS datasets

Examples of VA studies that have 

assessed healthcare use

Where to go for more help

4 
RESEARCHERS’ GUIDE TO VA DATA

Frayne, Berg, Holmes, et al., J Rehabil Res Dev

2010;47(8):709-718

October 29, 2012 5 

Objective: Examined how algorithm 

choice affected conclusions about 

mental illness-related disparities in 

length of stay

Study Design: Using a 2002 cohort 

of patients, tracked inpatient use in 

2003

Data Sources: VA Inpatient 

MedSAS datasets, others

Healthcare Use Construct: 

Inpatient events and Length of stay
RESEARCHERS’ GUIDE TO VA DATA

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Research Example II:

Luther, Neumayer, Henderson, et al., Am J Surg

2013;206:72-79

Objective: To conduct stageadjusted analyses of the utilization 

rates of breast-conserving surgery

Study Design: Retrospective cohort 

study of women Veterans diagnosed 

or receiving their initial treatment for 

breast cancer in 2000-2006 at VHA 

facilities

Data Sources: VA Inpatient and 

Outpatient MedSAS Datasets, VA 

Cancer Registry, among others

Healthcare Use Construct: 

 Surgical procedures
RESEARCHERS’ GUIDE TO VA DATA

Topics for Today

How has healthcare utilization been 

measured in VA studies?

Overview of Medical SAS datasets

Finding information in the Medical 

SAS datasets

Examples of VA studies that have 

assessed healthcare use

Where to go for more help

7 
RESEARCHERS’ GUIDE TO VA DATA

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Audience Poll

(Heidi to convert using poll function)

How would you rate your overall 

knowledge of the VA MedSAS 

datasets?

1 (Never Used); 

2; 

3; 

4; 

5 (Used Frequently, Very familiar)
RESEARCHERS’ GUIDE TO VA DATA

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Overview of Medical SAS Datasets

Medical SAS (MedSAS) Inpatient and 

Outpatient Datasets

– Comprehensive datasets for national VHA 

healthcare delivery

– Hosted on mainframe computer at Austin 

Information Technology Center (AITC)

– Inpatient and outpatient datasets
RESEARCHERS’ GUIDE TO VA DATA

• Available on a quarterly basis

• Researchers advised to use annual, closedout datasets

• Common element: patient identifier 

(scrambled SSN)

• After the NPCD shutdown (end of FY14), 

FY15 outpatient utilization data will only be 

available in SQL tables in the Corporate 

Data Warehouse

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Overview of Medical SAS Datasets
RESEARCHERS’ GUIDE TO VA DATA

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VA Data Flow 

to the Medical SAS Datasets

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*4 datasets within each category: Main, Bed Section, Procedure, Surgery 

Inpatient Datasets

Acute Care*

Extended Care*

Observation Care

Non-VA Care*

Outpatient Datasets

Visit

Event

Inpatient Encounters
RESEARCHERS’ GUIDE TO VA DATA

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VA Medical SAS Inpatient Datasets

4 datasets within each category of care

File Information Provided

Main Summary of entire stay (episode of 

care) and demographic information

Bed Section

Data for segment of stay defined by 

specialty of physician managing 

patient’s care

Procedure Information on up to 5 procedures 

on a given day

Surgery Information on up to 5 surgeries on 

a given day
RESEARCHERS’ GUIDE TO VA DATA

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VA Medical SAS Inpatient Datasets:

Acute Care

Datasets at AITC are named: MDPPRD.MDP.SAS.XXyy

XX = two letter reference code below; yy = two digit FY

File Reference Dates

Main PM 1970 - present 

Bed Section PB 1984 – present 

Procedure PP 1988 - present 

Surgery PS 1984 - present 
RESEARCHERS’ GUIDE TO VA DATA

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VA Medical SAS Outpatient Datasets

File Information Provided

Visit 

Reports services provided to a 

patient in a 24-hour period at a 

single facility 

Event Provides information about 

individual outpatient encounters

Inpatient 

Encounters 

Provides information about 

professional services received during 

inpatient stay
RESEARCHERS’ GUIDE TO VA DATA

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VA Medical SAS Outpatient Datasets

File Reference Dates

Visit SF 1980 - present 

Event SE 1998 – present 

Inpatient 

Encounters IE 2005 - present 

Datasets at AITC are named: MDPPRD.MDP.SAS.XXyy

XX = two letter reference code below; yy = two digit FY
RESEARCHERS’ GUIDE TO VA DATA

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16 

Primary 

Care Clinic 

Stop

Ophthalmology 

Clinic Stop

Physical 

Therapy 

Clinic Stop

Event Event Event

Visit

Visit vs. Event File

Patient’s 

Outpatient 

Clinic Stops

During One 

Day at One 

Facility 
RESEARCHERS’ GUIDE TO VA DATA

VA Medical SAS Outpatient Datasets

Clinic Stops

Clinics are identified using Clinic 

Stop Codes (equivalent to DSS 

Identifiers)

– Primary Clinic Stop Code (CL)

• Identifies production units or revenue centers 

for outpatient care

– Secondary Clinic Stop Code (CLC)

• Further specifies team, service, funding

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RESEARCHERS’ GUIDE TO VA DATA

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VA Medical SAS Outpatient Datasets

Clinic Stop Examples

– 216203 Telephone Audiology Rehab Support Service

216204 Telephone Speech Rehab Support Service

216210 Spinal Cord Injury Telephone Support

–

–

CL CLC

– 116329 Respiratory Therapy Procedures

– 116714 Respiratory Therapy Education

CL CLC
RESEARCHERS’ GUIDE TO VA DATA

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Outpatient Visit File (SF)

– One record per visit

Primary Clinic 

Stop Code 

Name % 

108 LABORATORY 20

323 PRIMARY CARE 

MEDICINE

12

338 TELEPHONE PRIMARY 

CARE

5 

502 MENTAL HEALTH 

CLINIC- INDIVIDUAL

4 

105 X-RAY 3 

– One VA 

facility per 

visit

– Up to 15 

primary clinic 

stops per visit 

at the given 

facility

– No diagnosis or procedure information

Top 5 Primary Clinic Stops in FY2012 

Visit File (from first 3 million records)
RESEARCHERS’ GUIDE TO VA DATA

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Outpatient Event File (SE)

– One record per clinic stop

Secondary Clinic 

Stop Code 

Name % 

(None) 63

117 NURSING 8 

125 SOCIAL WORK 

SERVICE

4 

185 PHYSICIAN 

EXTENDER (NP)

2 

323 PRIMARY CARE 

MEDICINE

2 

– One secondary 

clinic stop per 

record 

– No limit on # 

records/day 

– Combines 

diagnostic and 

procedural 

information in 

one dataset 

Top 5 Secondary Clinic Stops in 

FY2012 in Event File (from first 3 

million records)
RESEARCHERS’ GUIDE TO VA DATA

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Outpatient Event (SE) File

ICD-9 Codes: Up to 10 diagnoses per 

record

CPT-4 Codes: 

– Until FY2004: 15 procedures, no repeats allowed

– Since FY2005: 20 procedures, repetition allowed

Since FY2003, Encounter ID 

– Links Event dataset with HERC Outpatient 

Average Cost Dataset
RESEARCHERS’ GUIDE TO VA DATA

Inpatient Encounters File (IE)

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Primary Clinic 

Stop Code 

Name % 

105 X-RAY 9 

202 RECREATION 

THERAPY SERVICE

8 

205 PHYSICAL THERAPY 7 

166 CHAPLAIN SERVICEINDIVIDUAL6 

116 RESPIRATORY 

THERAPY

6 

– Encounter in 

clinic during 

inpatient stay

– Excludes 

services in 

outpatient SE 

file

– Data available 

beginning 

FY2005

Top 5 Primary Clinic Stops in FY2012 

Inpatient Encounters File (from first 3 

million records)
RESEARCHERS’ GUIDE TO VA DATA

Topics for Today

How has healthcare utilization been 

measured in VA studies?

Overview of Medical SAS datasets

Finding information in the Medical 

SAS datasets

Examples of VA studies that have 

assessed healthcare use

Where to go for more help

23
RESEARCHERS’ GUIDE TO VA DATA

Finding Information in the Medical SAS 

Datasets 

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RESEARCHERS’ GUIDE TO VA DATA

Where do you usually go to find 

information about VA data?

Write your answer on the white board!

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RESEARCHERS’ GUIDE TO VA DATA

Finding Information in the Medical SAS 

Datasets 

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RESEARCHERS’ GUIDE TO VA DATA

Finding Information in the Medical SAS 

Datasets 

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RESEARCHERS’ GUIDE TO VA DATA

Finding Information in the Medical SAS 

Datasets

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List of Variables and their 

Dataset Locations

Variable Name: DXLSF
RESEARCHERS’ GUIDE TO VA DATA

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Finding Information in the Inpatient Medical SAS 

Datasets to assess Admission and Discharge

All inpatient datasets include:

– Admission date and time

– VISN and station number (facility)

– Discharge date and time

– Discharge status

– Discharge type
RESEARCHERS’ GUIDE TO VA DATA

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What if you are only interested in veterans’ 

healthcare use? 

Can I identify non-veterans for exclusion?

Small number of patients (1-2%) receiving 

healthcare in VHA are not Veterans

– VA employees

– Veterans’ family members

In the MEDSAS Datasets

– Indicates if a particular stay or visit is covered 

because the patient is a Veteran

– HERC’s Technical Report: A Guide to Identifying No

Veteran Records in the Inpatient and Outpatient 

Databases, 2006

n-
RESEARCHERS’ GUIDE TO VA DATA

Excluding non-Veterans from MEDSAS 

Data: HERC Methods, 2006

Used the variables: Means Test, Period of 

Service, Compensation & Pension Status 

(Inpatient), & Eligibility (Outpatient) 

Results:

– Overall, non-Vets made up 0.97% of 

Inpatient records and 2.17% of Outpatient 

records

– For females, non-Vets made up 11.77% of 

Inpatient records and 22.09% of Outpatient 

records

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RESEARCHERS’ GUIDE TO VA DATA

To identify non-veterans 

Use the VSF

VA Vital Status File

– Created for best source of death dates

– Also contains a VET FLAG

– Two VSF that comprise info from multiple 

sources, including MEDSAS, DSS, enrollment 

files, others: 

• Master File: 17.3 million any VHA individuals

• Mini File: 15.4 million only those with “proof of 

veteran status” in one source

• Difference in Files (about 2 million) indicates 

those using VHA who may not be veterans

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RESEARCHERS’ GUIDE TO VA DATA

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Finding Information in the Inpatient Medical SAS 

Datasets to assess Physician Specialty

BEDSECN variable identifies specialty 

of physician managing patient’s care

– Found in Bed Section and Procedure 

datasets

– Contains treating specialty code

– One inpatient stay may have many 

bedsection stays
RESEARCHERS’ GUIDE TO VA DATA

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Finding Information in the Inpatient Medical SAS 

Datasets to assess Diagnoses

DXLSF: Primary Diagnosis for Admission

– Diagnosis initially assigned at admission

– May be different than DXPRIME if diagnosis 

changes after study/test results

– Not coded by HIM

DXPRIME: Principal Diagnosis

– Condition which, after study, is determined 

chiefly responsible for the admission to the 

hospital.

– Codes assigned by professional coders (HIM)

– Leads to the calculation of the DRG
RESEARCHERS’ GUIDE TO VA DATA

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Finding Information in the Inpatient Medical SAS 

Datasets to assess Diagnoses

DXF2 – DXF13*

– Secondary ICD-9-CM diagnosis codes for ful

hospital stay

– MAIN data set only 

DXLSB, DXB2-DXB5

– Diagnoses related to the Bed Section stay

l

*Number of secondary diagnoses codes changed from 9 to 12 

in FY2005
RESEARCHERS’ GUIDE TO VA DATA

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Finding Information in the Inpatient Medical SAS 

Datasets to assess Procedures

Procedure datasets contain:

– Procedures not performed in an operating room

– Dialysis type & number of dialysis treatments

Surgery datasets contain:

– Surgeries performed in operating room

A “procedure” in one facility may be 

considered “surgery” in another facility. 

Check both datasets. 

Inpatient MedSAS datasets use ICD-9 

procedure codes
RESEARCHERS’ GUIDE TO VA DATA

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Finding Information in the Inpatient Medical SAS 

Datasets to assess Length of Stay

Records are created at discharge for the full 

stay, even if the admission was in a prior 

year

– Exception: Claims for Non-VA Care included in 

dataset for year paid, not for year of care

Inpatient dataset includes length of stay

– LS=[(DISDAY – ADMITDAY) – (ABO + PASS)] 

with minimum value of 1 
RESEARCHERS’ GUIDE TO VA DATA

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–Outpatient Event (SE) 

• 1997 to present

–Inpatient Encounters 

(IE)

• 2005 to present

– DXLSF 

• Primary diagnosis

– DXF2-DXF10

• Secondary diagnoses

Finding Information in the Outpatient Medical SAS 

Datasets to assess Use by Diagnoses

DXLSF Values % 

30981 Posttraumatic stress

disorder

5

V6540 Other counseling NOS 4 

V6549 Other specified 

counseling

4 

4019 Unspecified essential 

hypertension

4 

25000 Diabetes mellitus 

without mention of 

complication

4 

Top 5 DXLSF in FY2012 SE File

(from first 3 million records) 
RESEARCHERS’ GUIDE TO VA DATA

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– Outpatient 

Event (SE) 

– Inpatient 

Encounters (IE)

– CPT1-CPT20*

– CPT-4 Codes

Finding Information in the Outpatient Medical SAS 

Datasets to assess Use of Procedures

CPT1 Values % 

98966 Telephone assessment by 

non-physician 

8 

99213 Moderate severity OP visit 

for established patient 

5 

99211 Minimal severity OP visit for 

established patient 

4 

99214 High severity OP visit for 

established patient 

4 

85025 CBC 3 

Top 5 CPT1 Codes in FY2012 SE File

(from first 3 million records)CPT

*Number of CPT codes changed from 15 to 20 in FY2005
RESEARCHERS’ GUIDE TO VA DATA

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– Physician 

specialty 

recorded using 

CMS provider 

class 

– PROV1-

PROV10

– Outpatient Event 

(SE)

– Inpatient 

Encounters (IE)

Finding Information in the Outpatient Medical SAS 

Datasets to assess Use by Provider Types

Provider 

Types

Values % 

181000 INTERNAL MEDICINE 11

182402 PATHOLOGY 9 

070900 REGISTERED NURSE 8 

115500 RESIDENT ALLOPATHIC 4 

070804 LICENSED PRACTICAL NURSE 4 

Top 5 Provider Types in FY2012 SE 

File (from first 3 million records)
RESEARCHERS’ GUIDE TO VA DATA

Topics for Today

How has healthcare utilization been 

measured in VA studies?

Overview of Medical SAS datasets

Finding information in the Medical 

SAS datasets

Examples of VA studies that have 

assessed healthcare use

Where to go for more help

41
RESEARCHERS’ GUIDE TO VA DATA

Research Example I

Mortensen, Copeland, Pugh, et al., Am J Medicine

2010;123:66-71

Objective: To assess frequency 

of diagnosis of pulmonary 

malignancy, after hospitalization 

for pneumonia

Study Design: Retrospective 

cohort, VA inpatients from 

FY2002-2007, age ≥ 65 years

Data Sources: VA Inpatient 

and Outpatient MedSAS 

Datasets, among others

Use Construct: Events after 

hospitalization

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RESEARCHERS’ GUIDE TO VA DATA

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Research Example I

Mortensen, Copeland, Pugh, et al., Am J Medicine

2010;123:66-71

Inclusion/exclusion criteria

– Were age 65 years or older on the date of 

admission 

– Had at least one outpatient clinic visit in the 

year preceding the index admission

– Received at least one active and filled 

outpatient medication within 90 days of 

admission 

– Hospitalized during FY 2002-2007

– Had a previously validated discharge diagnosis 

of pneumonia/influenza
RESEARCHERS’ GUIDE TO VA DATA

Research Example I

Mortensen, Copeland, Pugh, et al., Am J Medicine

2010;123:66-71

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Variables Post Hospitalization 

w/Pulmonary 

Malignancy

(N=3760)

No Pulmonary 

Malignancy

(N=36,984)

Pvalue

HospitalizationICU285 (8) 5471 (15) <.001

Hospitalizationmechanical 

ventilation

105 (3) 2627 (7) <.001

Mortality at 30d 48 (1) 5222 (14) <.001

Mortality at 90d 267 (7) 8184 (22) <.001

Length of Stay 6.21 (7.4) 8.1 (13.3) <.001
RESEARCHERS’ GUIDE TO VA DATA

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Research Example II:

Luther, Neumayer, Henderson, et al., Am J Surg

2013;206:72-79

Objective: To conduct stageadjusted analyses of the utilization 

rates of breast-conserving surgery

Study Design: Retrospective cohort 

study of women Veterans diagnosed 

or receiving their initial treatment for 

breast cancer in 2000-2006 at VHA 

facilities

Data Sources: VA Inpatient and 

Outpatient MedSAS Datasets, among 

others 

Use Construct: Surgical procedures
RESEARCHERS’ GUIDE TO VA DATA

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Research Example II:

Luther, Neumayer, Henderson, et al., Am J Surg

2013;206:72-79

Figure 1. The use of BCS and mastectomy in the VHA, 2000 to 2006.
RESEARCHERS’ GUIDE TO VA DATA

Topics for Today

How has healthcare utilization been 

measured in VA studies?

Overview of Medical SAS datasets

Finding information in the Medical 

SAS datasets

Examples of VA studies that have 

assessed healthcare use

Where to go for more help

47
RESEARCHERS’ GUIDE TO VA DATA

48

Obtaining Help

VIReC Website

– http://www.virec.research.va.gov

• Research User Guides (RUGs)

– Variable-level information

• Technical Reports

• Web-site “Toolkit for New Users of VA Data”

• Monthly Data Issue Briefs

Help Desk

– virec@va.gov

– (708) 202-2413 
RESEARCHERS’ GUIDE TO VA DATA

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Obtaining Help

HSRData Listserv

– Join at VIReC’s Intranet Web site

– Exchange of current information, ideas, 

questions, and answers about data and 

informatics issues affecting VA research

– Discussion among close to 700 VA only 

researchers, data stewards, managers, 

and other users

– Searchable archive of past discussions
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Questions?
RESEARCHERS’ GUIDE TO VA DATA

Next session:

January 6, 2014

Measuring Veterans Health Services Use in 

VA and Medicare

Kristin de Groot, MPH