U.S. Department of Health and Human Services 
 
Office of Inspector General 
 
 
Part D Plans Generally Include 
Drugs Commonly Used by 
Dual Eligibles: 2021 
 
 
 
 
Suzanne Murrin 
Deputy Inspector General for Evaluation and Inspections 
June 2021, OEI-05-21-00170  U.S. Department of Health and Human Services 
O  ffice of Inspector General 
Report in Brief 
 
Ju ne 2021, OEI-05-21-00170 
Part D Plans Generally Include Drugs 
Why OIG Did This Review 
The Patient Protection and  Commonly Used by Dual Eligibles: 2021 
Affordable Care Act (ACA) requires 
the Office of Inspector General (OIG) 
What OIG Found 
to conduct a study of the extent to  Key Takeaway 
Overall, we found that the rate of Part D 
which formularies used by Medicare 
plan formularies inclusion of the 195 drugs 
Part D plans include drugs commonly  Overall, we found that the 
commonly used by dual eligibles (i.e., 
used by full-benefit dual-eligible  rate of Part D plan 
individuals who are eligible for both 
individuals (i.e., individuals who are  formularies inclusion of the 
Medicare and Medicaid) is high, with some 
eligible for both Medicare and full  drugs commonly used by 
variation.  On average, Part D plan 
Medicaid benefits).  These individuals  dual eligibles is high, with 
formularies include 97 percent of the 
generally get drug coverage through  some variation.  Because 
195 commonly used drugs.  In addition, 
Medicare Part D.  Pursuant to the  some variation exists in 
74 percent of the commonly used drugs are 
ACA, OIG must annually issue a  formularies inclusion and 
included by all Part D plan formularies.  
report with recommendations as  utilization management of 
These results are largely unchanged from 
appropriate.  This is the eleventh  these drugs, some dual 
OIGs findings for formularies reported in 
report OIG has produced to meet  eligibles may need to make 
the mandated annual report from 2020, as 
this mandate.  additional efforts (e.g., 
well as from the findings in our reports 
appeal coverage decisions) 
from 2011 through 2019. 
How OIG Did This Review  to access the drugs they 
For this report, we determined  take.   
We also found that the percentage of drugs 
whether the 453 unique formularies 
to which plan formularies applied utilization 
used by the 5,128 Part D plans 
management tools remained the same between 2020 and 2021.  On average, 
operating in 2021 cover the 
formularies applied utilization management tools to 29 percent of the unique 
200 drugs most commonly used by 
drugs we reviewed in both 2020 and 2021. 
dual eligibles.  We also determined 
the extent to which plan formularies  What OIG Concludes 
applied utilization management tools  Inclusion rates for the 195 drugs commonly used by dual eligibles are largely 
to those commonly used drugs.  To  unchanged from the inclusion rates listed in our previous reports.  Part D 
create the list of the 200 drugs most  formularies include roughly the same high percentage of these commonly 
commonly used by dual eligibles, we  used drugs in 2021 as they did in 2020.   
used data from the 2018 Medicare 
Current Beneficiary Surveythe most  As mandated by the ACA, OIG will continue to monitor and produce annual 
recent data available at the time of  reports on the extent to which Part D plan formularies cover drugs that dual 
our study.  Of the top 200 drugs,  eligibles commonly use.  OIG has no recommendations at this time. 
195 are eligible for Part D 
prescription drug coverage, 2 are 
excluded from coverage, 1 is no 
longer offered as a prescription, and 
1 is a medical supply item covered by 
Part D.  One additional drug is 
eligible for Part D prescription drug 
coverage.  However, we did not 
include it in our analysis because we 
could not confidently project the use 
of  this drug to the entire dual eligible 
po pulation.   
TABLE OF CONTENTS 
 
 
 
 
BACKGROUND  1 
Methodology  7 
FINDINGS  12 
Part D plan formularies include between 89 and 100 percent of the drugs commonly used by  12 
dual eligibles 
Seventy-four percent of the drugs commonly used by dual eligibles are included in all Part D  14 
plan formularies 
The percentage of commonly used drugs to which plan formularies applied utilization  16 
management tools remained the same between 2020 and 2021 
CONCLUSION   19 
APPENDICES  21 
A.  Section 3313 of the Patient Protection and Affordable Care Act of 2010  21 
B.  List of mandated Office of Inspector General reports examining dual eligibles access to  22 
drugs under Part D 
C.  Commonly used drugs and rates of inclusion by formularies  23 
D.  Five drugs commonly used by dual eligibles were excluded from this analysis  30 
E.  Rates at which prescription drug plan formularies associated with stand-alone Medicare  31 
Part D plans or Medicare Advantage plans include commonly used drugs, by region 
ACKNOWLEDGMENTS AND CONTACT  33 
ABOUT THE OFFICE OF INSPECTOR GENERAL  34 
   
BACKGROUND 
 
 
Objectives 
1.  To determine the extent to which Part D plan formularies cover the drugs 
commonly used by dual eligibles. 
2.  To determine the extent to which Part D plan formularies applied utilization 
management tools to the drugs commonly used by dual eligibles. 
 
Pursuant to the Medicare Prescription Drug, Improvement, and Modernization Act of 
2003 (MMA), comprehensive prescription drug coverage under Medicare Part D is 
available to all Medicare beneficiaries through prescription drug plans (PDPs) and 
Medicare Advantage prescription drug plans (MA-PDs), hereinafter referred to 
collectively as Part D plans.1   
For beneficiaries who are eligible for both Medicare and Medicaid (hereinafter 
referred to as dual eligibles), Medicare subsidizes Part D plan premiums, deductibles, 
and other cost sharing up to a determined premium benchmark that varies by region.  
If dual eligibles enroll in Part D plans with premiums higher than the regional 
benchmark, they are responsible for paying the premium amounts above that 
benchmark. 
To control costs and ensure the safe use of drugs, Part D plans are allowed to 
establish formularies from which they may omit certain drugs from prescription 
coverage and are allowed to control drug utilization through utilization management 
tools.2  These tools include prior authorization, quantity limits, and step therapy.3  In 
addition, the Centers for Medicare & Medicaid Services (CMS) authorized Part D plans 
to use indication-based formulary design beginning in contract year 2020 to further 
control drug utilization.4 
_____________________________________________________________________________________________________________________________ 
1 MMA, P.L. No. 108-173 (enacted Dec. 8, 2003),  101, Social Security Act  1860D-1(a). 
2 A formulary is a list of drugs covered by a Part D plan.  Part D plans can exclude certain drugs from their 
formularies and can control utilization for formulary-included drugs within certain parameters.  Social 
Security Act  1860D-4(b) and (c). 
3 Prior authorizationoften required for very expensive drugsrequires that physicians obtain approval 
from Part D plans to prescribe a specific drug.  Quantity limits are intended to ensure that beneficiaries 
receive the proper dose and recommended duration of drug therapy.  Step therapy is the practice of 
beginning drug therapy for a medical condition with the drug therapy that is the most cost-effective or 
safest and progressing if necessary to drug therapy that is more costly or more risky. 
4 Indication-based formulary design allows Part D plans to limit certain drugs to specific indications.  
(An indication is a sign, symptom, or medical condition that leads to the recommendation of a treatment, 
test, or procedure.)  However, if a plan limits coverage of a drug to a specific indication, the plan must 
ensure that there is a therapeutically similar drug for other indications.  
Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2021 
OEI-05-21-00170  Background | 1  CMS annually reviews Part D plan formularies to ensure that they include a range of 
drugs in a broad distribution of therapeutic categories or classes.  CMS also assesses 
the utilization management tools present in each formulary. 
The Medicare Prescription Drug Benefit 
Beginning in 2006, the MMA made comprehensive prescription drug coverage under 
Medicare Part D available to all Medicare beneficiaries.5  Medicare beneficiaries 
generally have the option to enroll in a PDP and receive all other Medicare benefits 
on a fee-for-service basis, or to enroll in an MA-PD and receive all of their Medicare 
benefits, including prescription drug coverage, through managed care.6  As of 
January 2021, approximately 48.4 million of the 63.1 million Medicare beneficiaries 
were enrolled in a Part D plan. 
Part D plans are administered by private companiesknown as plan sponsorsthat 
contract with CMS to offer prescription drug coverage in one or more PDP or MA-PD 
regions.  CMS has designated 34 PDP regions and 26 MA-PD regions.  In 2021, plan 
sponsors offer 5,128 unique Part D plans, with many plan sponsors offering multiple 
Part D plans.  
Dual Eligibles Under Medicare Part D 
Approximately 12.3 million Medicare beneficiaries are dual eligibles.  For about 
8.8 million dual eligibles, referred to as full-benefit dual eligibles, Medicaid provides 
full Medicaid benefits, including Medicaid-covered services, and may also assist 
beneficiaries with premiums and cost sharing for Medicare fee-for-service or 
Medicare managed care.  For other dual eligibles, Medicaid does not provide 
Medicaid-covered services, but provides assistance with beneficiaries Medicare 
premiums or cost sharing, depending on their level of income and assets.7 
Dual eligibles are a particularly vulnerable population.  Overall, most dual eligibles 
have very low incomes86 percent have annual incomes below 150 percent of the 
Federal poverty level, compared with 22 percent of all other Medicare beneficiaries.  
Additionally, dual eligibles are in worse health than the average Medicare 
beneficiaryhalf are in fair or poor health, more than twice the rate of others in 
Medicare.8  Because of their self-reported health needs, dual eligibles may use more 
_____________________________________________________________________________________________________________________________ 
5 MMA, P.L. No. 108-173 (enacted Dec. 8, 2003),  101, Social Security Act  1860D-1(a). 
6 CMS, Prescription Drug Benefit Manual (PDBM), ch. 1,  10.1. 
7 Medicare Payment Advisory Commission and Medicaid and CHIP [Children's Health Insurance Program] 
Payment and Access Commission, Data Book: Beneficiaries Dually Eligible for Medicare and Medicaid
January 2018.  Accessed at https://www.macpac.gov/wp-content/uploads/2017/01/January-2018-
Beneficiaries-Dually-Eligible-for-Medicare-and-Medicaid-Data-Book.pdf on April 9, 2021. 
8 Kaiser Family Foundation, Medicares Role for Dual Eligible Beneficiaries.  Accessed at 
http://www.kff.org/medicare/upload/8138-02.pdf on March 19, 2021. 
Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2021 
OEI-05-21-00170  Background | 2  prescription drugs and health care services in general than other Medicare 
beneficiaries. 
Until December 31, 2005, dual eligibles received outpatient prescription drug benefits 
through Medicaid.  In January 2006, Medicare began covering outpatient prescription 
drugs for dual eligibles through Part D plans.9  
Medicare covers Part D plan premiums for dual eligibles up to a set benchmark.  The 
benchmark is a statutorily defined amount that is based on the average premium 
amounts for Part D plans for each region.10, 11  If dual eligibles enroll in Part D plans 
with premiums higher than the regional benchmark, they are responsible for paying 
the premium amounts above that benchmark.12  
Dual eligibles assignment to Part D plans 
When individuals become eligible for both Medicare and Medicaid, CMS randomly 
assigns those individuals to PDPs unless they have elected a specific Part D plan or 
have opted out of Part D prescription drug coverage.13  The PDPs to which CMS 
assigns dual eligibles must meet certain requirements, such as having a premium at or 
below the regional benchmark amount and offering basic prescription drug coverage 
(or equivalent).14  Basic prescription drug coverage is defined in terms of benefit 
structure (initial coverage, coverage gap, and catastrophic coverage) and costs (initial 
deductible and coinsurance). 
Because CMS does this PDP assignment on a random basis, dual eligibles may find 
themselves enrolled in PDPs that do not cover the specific drugs that they use, or that 
cover those specific drugs for only a limited set of indications.  However, unlike the 
general Medicare population, dual eligibles have up to three special election periods 
during the first 9 months of the year to find plans that cover the prescription drugs 
the dual eligibles require and switch plans if needed.15  When dual eligibles use 
_____________________________________________________________________________________________________________________________ 
9 MMA, P.L. No. 108-173 (enacted Dec. 8, 2003),  101, Social Security Act  1860D-1(a). 
10 Social Security Act  1860D-14(b); 42 CFR  423.780(b)(2)(i). 
11 Dual eligibles residing in territories are not eligible to receive cost-sharing assistance from Medicare.  
Consequently, there are no benchmarks for Part D plans offered in the territories.  Social Security Act 
 1860D-14(a)(3)(F). 
12 The ACA established a de minimis premium policy whereby a Part D plan may elect to charge dual 
eligibles the benchmark premium amount if the Part D plans basic premium exceeds the regional 
benchmark by a de minimis amount.  ACA, P.L. No. 111-148 (enacted Mar. 23, 2010),  3303, Social 
Security Act  1860D 14(a)(5).  For 2021, CMS set the de minimis amount at $2 above the regional 
benchmark.  
13 CMS, PDBM, ch. 3,  40.1.4. 
14 Ibid. 
15 83 Fed. Reg. 16440, 1651419 (Apr. 16, 2018).  In general, Medicare beneficiaries can switch Part D 
plans only once a year during a defined enrollment period.  Prior to 2019, dual eligibles could switch 
Part D plans monthly to find plans that covered the drugs they required.  
Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2021 
OEI-05-21-00170  Background | 3  a special election period to change plans, their prescription drug coverage under the 
new Part D plan becomes effective at the beginning of the following month. 
CMS annually reassigns some dual eligibles to new PDPs if those individuals current 
PDPs will have premiums above the regional benchmark premium for the following 
year.16  For dual eligibles who were randomly assigned to their current PDPs, CMS 
chooses new PDPs that will have premiums at or below the regional benchmark 
premium.17  For 2021, CMS reported reassigning approximately 1,107 Medicare 
beneficiariesincluding, but not exclusively, dual eligiblesbecause of premium 
increases. 
Part D Prescription Drug Coverage 
Under Part D, plans can establish formularies from which they may exclude drugs and 
control drug utilization within certain parameters.  These parameters are intended to 
balance Medicare beneficiaries needs for adequate prescription drug coverage with 
Part D plan sponsors needs to contain costs.  Generally, a formulary must include at 
least two drugs in each therapeutic category or class.18, 19  In addition, Part D plans 
must include drugs covered by Part D in certain categories and classes.20   
Starting in 2020, Part D plans are permitted to use indication-based formulary design.  
Plans that use this type of design limit formulary coverage of drugs to certain 
indications.  (An indication is a sign, symptom, or medical condition that leads to the 
recommendation of a treatment, test, or procedure.  The Food and Drug 
Administration (FDA) approves a drug for one or more indications.)  However, for 
each drug limited to certain indications, these plans must ensure that their formularies 
also cover at least one therapeutically similar drug for the nonformulary indications.21 
_____________________________________________________________________________________________________________________________ 
16 CMS, PDBM, ch. 3,  40.1.5.  CMS also reassigns beneficiaries who were assigned to plans that were 
terminated and will not be offered in the following year.  For 2021, CMS reassigned 121,685 beneficiaries 
because of terminated plans. 
17 Ibid. 
18 CMS, PDBM, ch. 6,  30.2.1. 
19 Therapeutic categories or classes classify drugs according to their most common intended uses.  For 
example, cardiovascular agents constitute a therapeutic class intended to affect the rate or intensity of 
cardiac contraction, blood vessel diameter, or blood volume. 
20 Social Security Act  1860D-4(b)(3)(G).  Current Part D policy requires sponsors to include in their 
formulariesexcept in limited circumstancesall drugs in six categories or classes: (1) antidepressants, 
(2) antipsychotics, (3) anticonvulsants, (4) immunosuppressants for treatment of transplant rejection, 
(5) antiretrovirals, and (6) antineoplastics.  CMS, PDBM, ch. 6,  30.2.5.   
21 CMS, Indication-Based Formulary Design Beginning in Contract Year (CY) 2020.  Accessed at 
https://www.cms.gov/Research-Statistics-Data-and-Systems/Computer-Data-and-
Systems/HPMS/Downloads/HPMS-Memos/Weekly/SysHPMS-Memo-2018-Aug-29th.pdf on 
March 22, 2021.  For example, a plan could cover a drug for plaque psoriasis, but not for Crohns disease, 
a condition for which the drug is also approved to treat.  The plan must then ensure that its formulary 
covers another, therapeutically similar drug for Crohns disease.   
Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2021 
OEI-05-21-00170  Background | 4  Part D plans may also control drug utilization by applying utilization management 
tools.  These tools include the following: requiring prior authorization to obtain drugs 
that are on plan formularies; establishing quantity limits; and requiring step therapy.  
Utilization management tools can help Part D plans and the Part D program limit the 
cost of prescription drug coverage by placing restrictions on the use of certain drugs. 
In addition to these drug coverage decisions that Part D plans make regarding 
individual formularies, certain categories of drugs are excluded from Medicare Part D 
prescription drug coverage as mandated by the MMA.22  For example, prescription 
vitamins, prescription mineral products, and nonprescription drugs are excluded from 
Part D prescription drug coverage.23 
Until 2013, barbiturates and benzodiazepines were excluded from Part D prescription 
drug coverage.  However, the Patient Protection and Affordable Care Act (ACA) 
reversed this exclusion, removing these two drug types from the list of drug classes 
ineligible for such coverage.24, 25   
CMS Efforts To Ensure Prescription Drug Coverage 
Formulary review 
CMS annually reviews Part D plan formularies to ensure that they include a range of 
drugs in a broad distribution of therapeutic categories or classes, as well as all drugs 
in specified therapeutic categories or classes.26  During this review, CMS analyzes 
formularies coverage of the drug classes most commonly prescribed for the Medicare 
population.  CMS intends for Part D plans to cover the most widely used medications, 
or therapeutically alternative medications (i.e., drugs from the same therapeutic 
category or class), for the most common conditions.  CMS uses Part D prescription 
drug data to identify the most commonly prescribed classes of drugs.27   
CMS also assesses each formularys utilization management tools to ensure 
consistency with current industry standards and with standards that are widely used 
with drugs for the elderly and people with disabilities.28, 29  
_____________________________________________________________________________________________________________________________ 
22 MMA, P.L. No. 108-173 (enacted Dec. 8, 2003),  101, Social Security Act  1860D-2(e). 
23 Social Security Act  1860D-2(e)(2), 1927(d)(2). 
24 ACA, P.L. No. 111-148 (enacted Mar. 23, 2010),  2502, Social Security Act  1927(d). 
25 CMS, Transition to Part D Coverage of Benzodiazepines and Barbiturates Beginning in 2013.  Accessed 
at http://www.cms.gov/Medicare/Prescription-Drug-
Coverage/PrescriptionDrugCovContra/Downloads/BenzoandBarbituratesin2013.pdf on March 20, 2021. 
26 CMS, PDBM, ch. 6,  30.2.7. 
27 Ibid. 
28 CMS, PDBM, ch. 6,  30.2.2. 
29 CMS, PDBM, ch. 6,  30.2.7. 
Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2021 
OEI-05-21-00170  Background | 5  Exceptions and appeals process 
CMS has implemented an exceptions and appeals process whereby beneficiaries can 
request coverage of nonformulary drugs or exceptions to utilization management 
tools that apply to formulary drugs.  When a Part D plan receives a prescribers 
statement supporting an exception request, the plan must notify the beneficiary of its 
determination within 72 hours or, for expedited requests, within 24 hours.30  If the 
beneficiarys plan makes an adverse determination, the beneficiary has the right to 
appeal.31  If the plan continues to deny the beneficiarys request, the beneficiary has 
additional appeal rights and may continue to appeal until those rights are exhausted.  
Alternatively, the beneficiary can work with his or her prescriber to determine whether 
there is an appropriate, therapeutically equivalent alternative drug on the plans 
formulary. 
Transitioning new enrollees to Part D 
CMS requires that Part D plans establish a transition process for new enrollees 
(including dual eligibles) who are transitioning to their respective Part D plans either 
from different Part D plans or from other prescription drug coverage.  During 
a Medicare beneficiarys first 90 days under a new Part D plan, the new plan must 
provide one temporary fill of a prescription when the beneficiary requests either a 
drug that is not in the plans formulary or a drug that requires prior authorization or 
step therapy under the formularys utilization management tools.32  The temporary fill 
accommodates the beneficiarys immediate drug needs the first time the beneficiary 
attempts to fill a prescription.  The transition period also allows the beneficiary time to 
work with the beneficiarys prescribing physician(s) to obtain prescriptions for 
therapeutically alternative drugs or to request a formulary exception from the Part D 
plan. 
Related Office of Inspector General Work 
In 2006, the Office of Inspector General (OIG) published a report assessing the extent 
to which PDP formularies included drugs commonly used by dual eligibles under 
Medicaid.  The study found that PDP formularies included between 76 and 
100 percent of the 178 drugs commonly used by dual eligibles under Medicaid prior 
to the implementation of Part D.  Approximately half of the 178 commonly used 
drugs were covered by all formularies.33   
_____________________________________________________________________________________________________________________________ 
30 CMS, Parts C & D Enrollee Grievances, Organization/Coverage Determinations, and Appeals Guidance, 
 40.5.3. 
31 CMS, Parts C & D Enrollee Grievances, Organization/Coverage Determinations, and Appeals Guidance, 
 50. 
32 CMS, PDBM, ch. 6,  30.4.4. 
33 OIG, Dual Eligibles Transition: Part D Formularies Inclusion of Commonly Used Drugs, 
OEI-05-06-00090, January 2006. 
Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2021 
OEI-05-21-00170  Background | 6  In 2011, OIG issued the first annual mandated report examining dual eligibles access 
to drugs under Medicare Part D.  (See Appendix A for the statutory mandate.)  
We have released an annual mandated report each year since then.  (See Appendix B 
for a list of these reports.)  This report is the eleventh report released. 
Methodology 
As mandated in the ACA, this study assessed the extent to which drugs commonly 
used by dual eligibles are included by Part D plan formularies.  To make this 
assessment, we evaluated formularies for Part D plans operating in 2021.  As part of 
our assessment, we included dual eligibles enrollment data from January 2021, the 
most recent enrollment data available from CMS at the time of our study.  We also 
compared the results of our 2021 study with those of our 2020 study.34   
The ACA did not define which drugs commonly used by dual eligibles we should 
review.  We defined drugs commonly used by dual eligibles as the 200 drugs with the 
highest utilization by dual eligibles as reported in the Medicare Current Beneficiary 
Survey (MCBS)i.e., the 2018 MCBS.  We used the MCBS because it contains drugs 
that dual eligibles received through multiple sources (e.g., Part D, Medicaid, and the 
Department of Veterans Affairs), and as such, it provides a comprehensive picture of 
drug utilization.  Of the 200 highest utilization drugs that we identified using the 
MCBS, 195 are eligible for coverage under Part D.  In this report, we refer to these 
195 Part D-eligible high-utilization drugs as commonly used drugs. 
For each study, OIG has gone beyond the ACAs mandate by reviewing drug coverage 
for all dual eligibles under Medicare Part D, rather than only for full-benefit dual 
eligibles.  With the data available for this study, we could not confidently identify and 
segregate full-benefit dual eligiblesand thus the drugs they usedfrom the total 
population of dual eligibles. 
In the current (2021) report and the previous 10 reports, we have also gone beyond 
the ACAs mandate by examining the utilization management tools that Part D plan 
formularies apply to the drugs commonly used by dual eligibles.  These tools may 
affect dual eligibles access, even in cases in which formularies include the commonly 
used drugs.  Analyzing the extent to which Part D plan formularies apply these tools 
to drugs commonly used by dual eligibles allows us to provide a comprehensive 
picture of Part D plan formularies coverage of, and dual eligibles access to, those 
drugs. 
Data sources 
MCBS.  We used the 2018 MCBS Cost and Use data to create a list of the 200 drugs 
with the highest utilization by dual eligibles.  The MCBS Cost and Use data contain 
information on hospitals, physicians, prescription drug costs, and prescription drug 
_____________________________________________________________________________________________________________________________ 
34 OIG, Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2020, OEI-05-20-00190, 
June 2020. 
Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2021 
OEI-05-21-00170  Background | 7  utilization.  The 2018 MCBS Cost and Use data were the most recent data available at 
the time of our study.  Historically, the list of the 200 drugs with the highest utilization 
by dual eligibles has remained largely unchanged from year to year.  The list for 
2021 overlapped by 90 percent with the list for 2020, which in turn overlapped by 
91 percent with the list for 2019.35  
The MCBS is a continuous, multipurpose survey that CMS conducts of a 
representative national sample of the Medicare population, including dual eligibles.  
Sampled Medicare beneficiaries are interviewed three times per year and asked which 
drugs they are taking and whether they have started taking any new drugs since the 
previous interview.  The MCBS also includes Part D prescription drug events for 
surveyed Medicare beneficiaries.  In 2018, the MCBS surveyed 15,237 Medicare 
beneficiaries, of whom 2,246 were dual eligibles who had used prescription drugs 
during the year (out of 3,896 dual-eligible survey respondents). 
First DataBank National Drug Data File.  We used the February 2021 First DataBank 
National Drug Data File to identify the drug product information for the 200 drugs 
with the highest utilization by dual eligibles.  The National Drug Data File is a 
database that contains informationsuch as drug name, therapeutic category or 
class, and the unique combination of active ingredientsfor each drug as defined by 
a National Drug Code (NDC).36 
Part D plan data.  In January 2021, we collected from CMS the formulary data and 
the plan data for Part D plans operating in 2021.  The formulary data includes Part D 
plans formularies and utilization management tools for plans operating in 2021.  In 
2021, there are 453 unique formularies offered by 5,128 Part D plans.  The plan data 
provides information such as the State in which a Part D plan is offered, whether the 
Part D plan is a PDP or an MA-PD, and whether the Part D plan premium is below the 
regional benchmark.   
We also collected 2021 enrollment data for Part D plans.  These data provide the 
number of dual eligibles enrolled in each Part D plan as of January 2021. 
Determining the most commonly used drugs 
To determine the drugs most commonly used by dual eligibles, we took the following 
steps: 
1.  We created a list of all drugs reported by dual eligibles surveyed in the 
2018 MCBS.  We excluded respondents from territories because they are not 
_____________________________________________________________________________________________________________________________ 
35 In 2020, we used 2017 MCBS data to create the list of the 200 drugs with the highest utilization by 
dual eligibles.  In 2019, we used 2016 MCBS data to create the list.  
36 An NDC is a three-part universal identifier that specifies the drug manufacturers name; the drug form 
and strength; and the package size. 
Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2021 
OEI-05-21-00170  Background | 8  eligible to receive cost-sharing assistance under Part D.  The MCBS listed 
145,646 drug events for 2,246 dual eligibles who did not reside in territories.37 
2.  We collapsed this list to a list of drugs based on their active ingredients.  To do 
this, we used the Ingredient List Identifier located in First DataBanks National 
Drug Data File.  For example, a multiple-source drug such as fluoxetine 
hydrochloride (the active ingredient for the brand-name drug Prozac) has only 
one entry on our list, covering all strengths of both the brand-name drug 
Prozac and the available generic versions of fluoxetine hydrochloride.  From 
this point forward, unless otherwise stated, we will use the term drug to refer 
to any drug in the same Ingredient List Identifier category, and the term 
unique drug to refer to an NDC corresponding to a drug, as a given drug can 
have multiple NDCs.  This process left 145,646 drug events associated with 
861 drugs.   
3.  We ranked the 861 drugs by frequency of utilization, weighting the drug-event 
information from MCBS by sample weight. 
4.  We selected the 200 drugs with the highest utilization by dual eligibles.  For a 
full list of the top 200 drugs, see Appendix C. 
5.  We removed all drugs not covered under Part D.  Of the 200 drugs with the 
highest utilization, 195 are eligible under Part D.  Two fall into a drug category 
excluded under Part D.  (For details on the two drugs excluded under Part D, 
see Appendix D.)  One drug is no longer offered as a prescription.  An 
additional drug is eligible for Part D prescription drug coverage.  However, we 
did not include it in our analysis becausealthough it is eligible under 
Part DMedicare considers it to be a medical supply item.  We did not include 
another drug in our analysis because we could not confidently project the use 
of this drug to the entire dual-eligible population.  
Formulary analysis 
We analyzed the 453 unique Part D plan formularies to determine their rates of 
inclusion of the 195 drugs commonly used by dual eligibles.  We counted a drug as 
included in a Part D plans formulary if the formulary included the active ingredient.   
Low rates of inclusion by formularies.  We determined which of the 195 commonly 
used drugs had low rates of inclusion by formularies by counting how many of the 
453 formularies covered each drug.  We considered a drug to have a low rate of 
inclusion if it was included by less than 75 percent of formularies.  For such drugs, we 
counted the number of drugs (if any) that each formulary covered in the same 
_____________________________________________________________________________________________________________________________ 
37 For the purposes of this report, a drug event is an MCBS survey response indicating that the 
responding beneficiary was prescribed a specific drug at least once in 2018.  For example, 1 MCBS survey 
respondent was prescribed lorazepam 13 times in 2018.  We counted this beneficiary/drug combination 
as 13 drug events. 
Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2021 
OEI-05-21-00170  Background | 9  therapeutic category or class.  We conducted this analysis to ensure that dual eligibles 
have access to therapeutically similar drugs.  
Utilization management tools.  We determined the extent to which Part D plans 
apply utilization management tools to the 195 drugs that we reviewed.  The tools that 
we reviewed are prior authorization, quantity limits, and step therapy. 
To determine the extent to which Part D plan formularies applied utilization 
management tools to the 195 commonly used drugs, we conducted an analysis of the 
NDCs that correspond to the commonly used drugs.  Part D plan formularies do not 
apply utilization management tools at the active ingredient level.  Rather, Part D plan 
formularies apply utilization management tools at a more specific level that identifies 
whether a drug is brand-name or generic and its dosage form, strength, and route of 
administration, irrespective of package size.  To conduct this analysis, we determined 
the NDCs (unique drugs) associated with each of the 195 commonly used drugs that 
are on each Part D formulary.  We then calculated the percentage of unique drugs to 
which each Part D plan formulary applies utilization management tools. 
Enrollment analysis 
We weighted the formulary analysis by dual-eligible enrollment and weighted the 
analysis of utilization management tools by both dual-eligible enrollment and 
Medicare enrollment.  To do this, we applied enrollment data from January 2021 to 
Part D plans available in 2021. 
Data limitations 
We did not assess individual dual eligibles prescription drug use or whether 
individual dual eligibles are enrolled in Part D plans that include the specific drugs 
that each individual uses.  Because we developed our list of commonly used drugs by 
using a sample of dual eligibles who responded to the MCBS, a particular dual eligible 
might not use any of the drugs on our list.  However, the drugs most commonly used 
by dual-eligible participants in the 2018 MCBS survey account for 88 percent of all 
prescriptions dispensed to the dual-eligible respondents in the 2018 MCBS. 
We also did not assess the impact of indication-based formulary design on dual 
eligibles access to prescription drugs.  The formulary data we used for this analysis 
do not include sufficient details for us to determine which drugs were covered for 
only a limited number of indications.  As a result, some beneficiaries included in our 
analysis may not be able to access all commonly used drugs covered by their 
respective Part D plans because certain drugs are not covered for all indications.  
However, CMS noted that very few Part D plans are using indication-based formulary 
design in 2021.  
 
 
Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2021 
OEI-05-21-00170  Background | 10  Standards 
We conducted this study in accordance with the Quality Standards for Inspection and 
Evaluation issued by the Council of the Inspectors General on Integrity and Efficiency. 
 
Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2021 
OEI-05-21-00170  Background | 11   
FINDINGS 
 
Part D plan formularies include between 89 and 100 percent of 
the drugs commonly used by dual eligibles 
On average, Part D plan formularies include 97 percent of the drugs commonly used 
by dual eligibles.  Of the 453 unique formularies used by Part D plans in 2021, 
5 formularies include 100 percent of the commonly used drugs.  At the other end of 
the inclusion range, two formularies include 89 percent of the commonly used drugs.  
Exhibit 1 provides a breakdown of the formularies inclusion rates for the drugs most 
commonly used by dual eligibles.  CMS generally requires Part D plan formularies to 
include at least two drugsrather than all drugsin each therapeutic category or 
class.  Therefore, Part D plan formularies may still meet CMSs formulary requirements 
even if the formularies do not include all of the drugs we identified as commonly used 
by dual eligibles.  
Exhibit 1: More than 4 in 5 of the 453 Part D plan formularies cover at least 
96 percent of the drugs commonly used by dual eligibles. 
 
      Source: OIG analysis of formulary inclusion of drugs commonly used by dual eligibles, 2021. 
Part D plan formularies rates of inclusion of the drugs commonly used by dual 
eligibles in 2021 did not change from the rates in 2020.  The average rate of inclusion 
remained at 97 percent between 2020 and 2021.  The range of inclusion rates also 
remained the same between 2020 and 2021; inclusion rates ranged from 89 to 
100 percent in both 2020 and 2021. 
Nationally, PDP and MA-PD formularies have similar rates of inclusion of the drugs 
commonly used by dual eligibles, averaging 95 percent and 97 percent, respectively.  
For PDP formularies, the rates of inclusion range from 89 to 99 percent.  For MA-PD 
formularies, the rates of inclusion range from 89 to 100 percent.  Nine formularies
Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2021 
OEI-05-21-00170  Findings | 12  2 percent of the 453 unique formularies used by Part D plans in 2021are used by 
both PDPs and MA-PDs. 
Regionally, all dual eligibles have the choice of a Part D plan that includes at least 
98 percent of the commonly used drugs.  Every PDP region has a plan that includes 
99 percent of the commonly used drugs, while every MA-PD region has a plan that 
includes at least 98 percent of the commonly used drugs.  Appendix E provides a 
breakdown of formularies rates of inclusion of the drugs by PDP and MA-PD region. 
On average, formularies for Part D plans with premiums below 
the regional benchmark include 97 percent of the drugs 
commonly used by dual eligibles 
The percentage of drugs included in formularies used by Part D plans with premiums 
below the regional benchmark is important because dual eligibles are automatically 
enrolled inor annually reassigned tosuch plans.  For drugs commonly used by 
dual eligibles, formularies for such plans have rates of inclusion that range from 
91 percent to 100 percent.  Approximately 66 percent of dual eligibles are enrolled in 
Part D plans with premiums below the regional benchmark. 
Almost all dual eligibles are enrolled in Part D plans that include 
at least 90 percent of the drugs commonly used by dual eligibles 
Of the approximately 11 million dual eligibles enrolled in Part D plans, almost 
100 percent are enrolled in Part D plans that use formularies that include at least 
90 percent of the commonly used drugs.  Less than 1 percent of dual eligibles are 
enrolled in Part D plans that use formularies that include less than 90 percent of these 
drugs.  Exhibit 2 provides a breakdown of dual eligibles enrollment in Part D plans by 
the rates at which the plans formularies include the commonly used drugs. 
Exhibit 2: Most dual eligibles are enrolled in Part D plans that include at 
least 90 percent of the drugs commonly used by dual eligibles. 
Part D Plans With Formularies That Include:  Number of Dual  Percentage of Dual 
Eligibles Enrolled  Eligibles Enrolled 
100% of commonly used drugs  4,414  0.04% 
95% to 99% of commonly used drugs  10,167,355  91.17% 
90% to 94% of commonly used drugs  950,374  8.52% 
86% to 89% of commonly used drugs  30,150  0.27% 
     Total  11,152,293  100% 
Source: OIG analysis of formulary inclusion of drugs commonly used by dual eligibles and dual eligibles enrollment, 
2021. 
Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2021 
OEI-05-21-00170  Findings | 13  The percentage of dual eligibles enrolled in Part D plans that include at least 
90 percent of the drugs commonly used by dual eligibles increased from 95 percent 
in 2020 to nearly 100 percent in 2021. 
Seventy-four percent of the drugs commonly used by dual 
eligibles are included in all Part D plan formularies 
Because most of the commonly used drugs are included in a large percentage of 
formularies, dual eligibles can be confident that regardless of the Part D plan in which 
they are enrolled, the plans formulary will include many of these drugs.  By drug, 
inclusion in formularies ranges from 43 percent to 100 percent.  At one end of the 
range, there is a drug that is included in 43 percent of Part D plan formularies; at the 
other end, 145 drugs are included in all plan formularies.  The average drugs rate of 
inclusion in formularies is 97 percent.  Exhibit 3 shows the rates at which formularies 
include the 195 drugs.  Appendix C lists the 195 drugs and the rates at which 
formularies include them. 
Exhibit 3: Nearly three-quarters of the drugs most commonly used by dual 
eligibles are included in all Part D plan formularies. 
Percentage  Percentage of the 195 Commonly 
of the 453  Used Drugs Included in Formularies 
Formularies 
100%  74% 
(145 drugs) 
85% to 99%  17% 
(33 drugs) 
76% to 84%  3% 
(6 drugs) 
43% to 75%  6% 
(11 drugs) 
     Total  100% 
(195 drugs) 
Source: OIG analysis of formulary inclusion of drugs commonly used by dual eligibles, 2021. 
The percentage of drugs commonly used by dual eligibles that were included in all 
formularies decreased slightly in 2021.  All formularies included 74 percent of the 
commonly used drugs in 2021, compared to 75 percent in 2020.   
Part D plan formularies include certain drugs less frequently than 
others 
Of the commonly used drugs, 6 percent (11 drugs) are included by less than 
75 percent of Part D plan formularies.  Exhibit 4 provides the percentage of 
formularies covering each of these 11 drugs. 
Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2021 
OEI-05-21-00170  Findings | 14  All 11 drugs are brand-name drugs, which are typically more costly than generic 
drugs.  Six of the 11 drugs had a primary indication for diabetes therapy, and the 
remaining 5 drugs treat a variety of conditions, including heartburn and chronic 
obstructive pulmonary disease. 
Exhibit 4: Drugs included by less than 75 percent of Part D plan formularies 
were most frequently used for diabetes therapy. 
 
Generic Name of Drug  Primary Indication(s)  Rate of Inclusion 
by Formularies 
Budesonide/formoterol fumarate*  Asthma  73% 
Insulin detemir*  Diabetes  70% 
Insulin aspart*  Diabetes  70% 
Umeclidinium bromide  Chronic obstructive pulmonary  69% 
disease 
Dapagliflozin propanediol  Diabetes  66% 
Insulin degludec  Diabetes  66% 
Tiotropium bromide*  Chronic obstructive pulmonary  66% 
disease 
Dexlansoprazole*  Gastroesophageal reflux disease  50% 
Lubiprostone  Chronic constipation  49% 
Insulin lispro*  Diabetes  44% 
Canagliflozin*  Diabetes  43% 
Source: OIG analysis of formulary inclusion of drugs commonly used by dual eligibles, 2021. 
* These drugs also had low rates of formulary inclusion in 2020. 
Although Part D formularies frequently omit these 11 drugs, they all cover other drugs 
in the same respective therapeutic classes.  For each of these 11 drugs, 100 percent of 
formularies cover at least 1 drug in the same therapeutic class that is also on the list 
of 195 drugs commonly used by dual eligibles. 
The number of drugs included by less than 75 percent of formularies increased 
between 2020 and 2021from 8 drugs in 2020 to 11 drugs in 2021.  There are seven 
drugs with low inclusion rates in 2021 that were also on the list of commonly used 
drugs with low inclusion rates in our 2020 report; we note these seven drugs with 
asterisks in Exhibit 4 (above).  Five of these seven drugs were also on the list of drugs 
with low inclusion rates in our 2019 report. 
If a formulary does not include a particular drug, a dual eligible has three options, all 
of which require taking additional action: 
  Obtaining a therapeutically equivalent alternative drug that is included by the 
plans formulary.  (This option necessitates getting a new prescription from the 
dual eligibles doctor.) 
Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2021 
OEI-05-21-00170  Findings | 15    Going through an appeals process to obtain coverage of a nonformulary drug 
by submitting a statement of medical necessity from the dual eligibles 
physician.38 
  Switching to a Part D plan with a formulary that does include the drug.  Dual 
eligibles can make such a switch once per calendar quarter during the first 
9 months of the year, with the new coverage becoming effective the following 
month.39 
The average percentage of commonly used drugs to which plan 
formularies applied utilization management tools remained the 
same between 2020 and 2021 
For the unique drugs that compose the list of commonly used drugs, the average 
percentage to which Part D plan formularies applied utilization management tools 
was 29 percent in both 2020 and 2021.  Plans with premiums below the regional 
benchmarks used utilization management tools less frequently than all plans; on 
average, formularies of these plans used utilization management tools for 24 percent 
of their drugs.  See Exhibit 5 for a breakdown of the 2020 percentage of unique drugs 
to which Part D plan formularies applied utilization management tools as well as the 
2021 percentage. 
   
_____________________________________________________________________________________________________________________________ 
38 CMS, Parts C & D Enrollee Grievances, Organization/Coverage Determinations, and Appeals Guidance, 
ch. 18,  40.5. 
39 83 Fed. Reg. 16440, 16519 (Apr. 16, 2018).  
Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2021 
OEI-05-21-00170  Findings | 16  Exhibit 5: Part D plan formularies application of utilization management tools shifted 
slightly between 2020 and 2021 for commonly used drugs. 
Percentage of Unique  Number of 2020  Percentage of  Number of 2021  Percentage of 
Drugs to Which Plan  Part D Plan  2020 Part D Plan  Part D Plan  2021 Part D Plan 
Formularies Applied  Formularies  Formularies  Formularies  Formularies 
Utilization Management 
Tools  
Greater than 40%  72  16%  75  17% 
30% to 39%  118  26%  179  40% 
20% to 29%  151  34%  90  20% 
10% to 19%  100  22%  88  19% 
Less than 10%  7  2%  21  5% 
     Totals  448  100%  453  100% 
Source: OIG analysis of formulary inclusion of drugs commonly used by dual eligibles, 2021. 
Although utilization management tools can restrict beneficiaries access to drugs, they 
are important tools for managing costs in Medicare and ensuring the appropriate 
utilization of drugs.  For example, in 2013, CMS set forth expectations for reviews of 
opioid overutilization to help ensure that opioids are appropriately prescribed and 
used.40  
The percentage of unique drugs for which formularies applied the utilization 
management tools of quantity limits, prior authorization, or step therapy41 changed 
slightly between 2020 and 2021.  On average, formularies applied quantity limits to 
27 percent of drugs in 2021 (an increase of 1 percentage point from 2020); required 
prior authorization for 3 percent of drugs; and required step therapy for 1 percent of 
unique drugs. 
The percentage of drugs to which plan formularies apply specific utilization 
management tools varies widely.  In 2021, some formularies apply utilization 
management tools to very few of the unique drugs, whereas at the other end of the 
range, some formularies applied tools to 45 percent of the unique drugs.  More 
specifically, formularies apply quantity limits to between 0 and 44 percent of unique 
drugs; require prior authorization for between less than 0 percent and 9 percent of 
unique drugs; and require step therapy for between 0 and 7 percent of unique drugs. 
Looking at enrollment across plans provides a slightly different picture than looking 
only at plans themselves.  On average, plan formularies in 2021 apply utilization 
management tools to 29 percent of unique drugs.  However, dual eligibles tend to be 
enrolled in plans with formularies that apply these tools at a slightly higher rate.  In 
_____________________________________________________________________________________________________________________________ 
40 CMS, Improving Drug Utilization Review Controls in Part D (Excerpt from Final 2013 Call Letter 
04-02-2012).  Accessed at https://www.cms.gov/medicare/prescription-drug-
coverage/prescriptiondrugcovcontra/downloads/improving-dur-controls-in-part-d.pdf on April 8, 2021. 
41 See footnote 3 for explanations of quantity limits, prior authorization, and step therapy. 
Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2021 
OEI-05-21-00170  Findings | 17  2021, the median plan weighted by dual-eligible enrollment applies such tools to 
34 percent of unique drugs; in 2020, the figure was 31 percent.  Similarly, the median 
plan weighted by overall Medicare enrollment applies these tools to 34 percent of 
unique drugs in 2021; in 2020, the figure was 32 percent. 
Both dual eligibles and Medicare beneficiaries overall tend to be enrolled in plans 
with formularies that apply utilization management tools to between 20 and 
39 percent of unique drugs.  In 2021, 85 percent of dual eligibles and 78 percent of 
Medicare beneficiaries overall were enrolled in plans with formularies in this range.   
In 2021, there was a decrease in the percentage of Medicare beneficiaries who were 
enrolled in plans that applied utilization management tools to more than 40 percent 
of unique drugs.  In 2020, 17 percent of dual eligibles and 22 percent of Medicare 
beneficiaries overall were enrolled in plans that applied utilization management tools 
to more than 40 percent of unique drugs.  These figures decreased to 10 percent and 
16 percent, respectively, in 2021.  However, there was an increase in the percentage of 
beneficiaries who were enrolled in plans that applied utilization management tools to 
30 percent to 39 percent of unique drugs.  Exhibit 6 shows enrollment in Part D plans 
by dual eligibles and Medicare beneficiaries, as broken down by the percentages at 
which the plans formularies applied utilization management tools. 
Exhibit 6: The number of beneficiaries who were enrolled in plans that applied utilization 
management tools to more than 40 percent of unique drugs decreased from 2020 to 
2021. 
Percentage of Unique Drugs  Percentage of  Percentage of  Percentage of  Percentage of 
to Which Plan Formularies  Dual Eligibles  Medicare  Dual Eligibles  Medicare 
Applied Utilization  Enrolled, 2020  Beneficiaries  Enrolled, 2021  Beneficiaries 
Management Tools  Enrolled, 2020  Enrolled, 2021 
Greater than 40%   17%  22%  10%  16% 
30% to 39%  40%  44%  74%  68% 
20% to 29%  37%  27%  11%  10% 
10% to 19%  4%  4%  3%  3% 
Less than 10%  2%  3%  2%  3% 
     Totals  100%  100%  100%  100% 
Source: OIG analysis of formulary inclusion of drugs commonly used by Medicare beneficiaries and dual eligibles, 2021. 
Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2021 
OEI-05-21-00170  Findings | 18   
CONCLUSION 
 
 
When establishing formularies and applying utilization management tools, Part D 
plans need to balance Medicare beneficiaries needs for adequate prescription drug 
coverage with the need to contain costs for plan sponsors and for the Part D 
program.  By law and under CMS policy, Part D plan formularies do not generally have 
to include every available drug.  Rather, to meet CMSs formulary requirements, they 
must include at least two drugs in each therapeutic category or class.  For example, 
for each of the 11 drugs that this report identifies as being included by less than 
75 percent of Part D plan formularies, all Part D plan formularies cover at least 
1 therapeutically equivalent alternative drug.  Additionally, starting in 2020, Part D 
plans are authorized to limit access to some drugs to only certain indications, 
provided that the plans also include a therapeutically similar drug that covers 
nonformulary indications as well.  Part D plan formularies may also institute utilization 
management tools to ensure appropriate utilization, as well as to control costs. 
For the drugs commonly used by dual eligibles, we found that the rate of formulary 
inclusion is high, with some variation.  On average, Part D plan formularies include 
97 percent of the commonly used drugs.  Part D plan formularies inclusion of the 
commonly used drugs ranges from 89 percent to 100 percent.  Formulary inclusion 
rates are similar for PDPs and MA-PDs.  Further, formularies for Part D plans with 
premiums below the regional benchmark include the commonly used drugs at a rate 
similar to that of Part D plan formularies overall.  However, to the extent that Part D 
sponsors implement indication-based formulary designs in the future, some dual 
eligibles may be unable to access all drugs covered by their plans formularies. 
Inclusion rates for the 195 drugs commonly used by dual eligibles are largely 
unchanged from those listed in OIGs 2020 report.  Part D plan formularies include 
roughly the same percentage of these commonly used drugs in 2021 as they did in 
2020.  Enrollment in plans that cover at least 90 percent of unique drugs increased, 
with almost 100 percent of dual eligibles enrolled in such plans in 2021, compared to 
95 percent of dual eligibles in 2020.   
Because some variation exists in the inclusion by Part D plan formularies of the 
commonly used drugs and in Part D plan formularies application of utilization 
management tools to these drugs, some dual eligibles may need to make additional 
efforts to access the drugs they take.  These dual eligibles could appeal prescription 
drug coverage decisions, switch prescription drugs, or switch Part D plans.  Because 
these scenarios require additional effort by dual eligibles, they may result in 
administrative barriers to accessing certain prescription drugs. 
As mandated by the ACA, OIG will continue to monitor and produce annual reports 
on the extent to which Part D plan formularies cover drugs that dual eligibles 
Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2021 
OEI-05-21-00170  Conclusion / Recommendations | 19  commonly use.  OIG has no recommendations based on this or previous annual 
mandated reports examining dual eligibles access to drugs under Medicare Part D.
Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2021 
OEI-05-21-00170  Conclusion / Recommendations | 20   
APPENDIX A 
 
Section 3313 of the Patient Protection and Affordable Care Act 
of 2010  
SEC. 3313.  OFFICE OF THE INSPECTOR GENERAL STUDIES AND REPORTS. 
(a)  STUDY AND ANNUAL REPORT ON PART D FORMULARIES INCLUSION OF DRUGS 
COMMONLY USED BY DUAL ELIGIBLES. 
(1)  STUDY.The Inspector General of the Department of Health and Human Services 
shall conduct a study of the extent to which formularies used by prescription drug 
plans and MA-PD plans under Part D include drugs commonly used by full-benefit 
dual eligible individuals (as defined in section 1935(c)(6) of the Social Security Act 
(42 U.S.C. 1396u5(c)(6)). 
(2)  ANNUAL REPORTS.Not later than July 1 of each year (beginning with 2011), the 
Inspector General shall submit to Congress a report on the study conducted under 
paragraph (1), together with such recommendations as the Inspector General 
determines appropriate. 
Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2021 
OEI-05-21-00170  Appendix A | 21   
APPENDIX B 
 
List of mandated Office of Inspector General reports examining 
dual eligibles access to drugs under Part D 
OIG, Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2011, 
OEI-05-10-00390, April 2011 
OIG, Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2012, 
OEI-05-12-00060, June 2012 
OIG, Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2013, 
OEI-05-13-00090, June 2013 
OIG, Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2014, 
OEI-05-14-00170, June 2014 
OIG, Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2015, 
OEI-05-15-00120, June 2015 
OIG, Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2016, 
OEI-05-16-00090, June 2016 
OIG, Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2017, 
OEI-05-17-00016, June 2017 
OIG, Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2018, 
OEI-05-18-00240, June 2018 
OIG, Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2019, 
OEI-05-19-00220, June 2019 
OIG, Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2020, 
OEI-05-20-00190, June 2020 
 
 
Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2021 
OEI-05-21-00170  Appendix B | 22   
APPENDIX C 
 
Commonly used drugs and rates of inclusion by formularies  
The 200 drugs with the highest utilization by dual eligibles 
 
Generic Name  Sample  Projected  95-Percent Confidence Interval  Number of  Percentage 
Size  Drug  Formularies  of 
Events  Including  Formularies 
Drug  Including 
Lower Bound  Upper Bound 
Drug 
Atorvastatin calcium  3,384  28,174,319  24,569,308  31,779,331  453  100% 
Amlodipine besylate  3,364  27,598,148  23,526,192  31,670,105  453  100% 
Lisinopril  3,076  23,968,857  20,237,213  27,700,502  453  100% 
Metformin hydrochloride  2,525  22,650,779  19,576,827  25,724,732  453  100% 
Levothyroxine sodium  4,314  22,350,773  19,607,142  25,094,404  453  100% 
Omeprazole  3,181  21,621,199  18,653,646  24,588,753  453  100% 
Gabapentin  3,166  18,873,306  16,453,162  21,293,451  453  100% 
Furosemide  3,583  17,938,241  15,809,058  20,067,425  453  100% 
Hydrocodone/acetaminophen  2,318  12,892,790  10,679,170  15,106,409  453  100% 
Simvastatin  1,600  12,845,632  10,935,571  14,755,694  453  100% 
Losartan potassium  1,491  12,048,428  10,199,279  13,897,577  453  100% 
Metoprolol succinate  1,505  11,889,664  9,848,185  13,931,143  453  100% 
Potassium chloride  2,453  11,691,408  10,098,504  13,284,311  453  100% 
Nystatin  2,743  11,639,448  6,891,503  16,387,393  453  100% 
Metoprolol tartrate  1,887  11,555,637  9,744,667  13,366,606  453  100% 
Albuterol sulfate  1,676  11,511,998  9,679,130  13,344,865  453  100% 
Pantoprazole sodium  1,849  10,253,207  8,649,510  11,856,905  453  100% 
Sertraline hydrochloride  1,513  9,690,874  7,778,666  11,603,083  453  100% 
Hydrochlorothiazide  1,318  9,601,137  7,762,928  11,439,346  453  100% 
Carvedilol  1,211  9,464,034  7,629,305  11,298,763  453  100% 
Ranitidine hydrochloride*  1,308  9,151,420  7,129,381  11,173,458  Excluded       Excluded 
Montelukast sodium  1,210  8,737,913  6,615,464  10,860,362  453  100% 
Clopidogrel bisulfate  1,243  8,609,383  7,068,282  10,150,484  453  100% 
Trazodone hydrochloride  1,423  7,991,832  6,539,218  9,444,447  453  100% 
Fluticasone propionate  1,120  7,393,022  5,939,647  8,846,397  453  100% 
Quetiapine fumarate  1,415  7,348,812  5,186,019  9,511,605  453  100% 
Glipizide  671  7,162,346  5,596,320  8,728,371  453  100% 
Pravastatin sodium  796  7,107,304  5,696,312  8,518,297  453  100% 
 
Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2021 
OEI-05-21-00170  Appendix C | 23  The 200 drugs with the highest utilization by dual eligibles, continued 
Generic Name  Sample  Projected  95-Percent Confidence Interval  Number of  Percentage 
Size  Drug  Formularies  of 
Events  Including  Formularies 
Drug  Including 
Lower Bound  Upper Bound  Drug 
Tramadol hydrochloride  1,538  7,094,167  5,816,108  8,372,226  453  100% 
Insulin glargine, hum.rec.anlog  913  7,043,943  5,665,225  8,422,662  453  100% 
Tamsulosin hydrochloride  1,121  6,459,519  5,386,026  7,533,011  453  100% 
Rosuvastatin calcium  623  6,455,969  5,022,005  7,889,932  453  100% 
Warfarin sodium  1,461  6,227,617  4,948,224  7,507,009  453  100% 
Citalopram hydrobromide  1,193  6,162,335  4,905,285  7,419,386  453  100% 
Duloxetine hydrochloride  1,027  5,762,753  4,686,629  6,838,877  453  100% 
Alprazolam  1,001  5,721,511  4,070,707  7,372,316  431  95% 
Bupropion hydrochloride  842  5,671,080  4,278,586  7,063,573  453  100% 
Allopurinol  700  5,611,769  4,097,596  7,125,942  453  100% 
Escitalopram oxalate  1,005  5,458,985  3,980,923  6,937,048  453  100% 
Clonazepam  1,021  5,412,372  3,844,548  6,980,196  453  100% 
Alendronate sodium  634  5,311,767  4,332,803  6,290,730  453  100% 
Fluoxetine hydrochloride  778  5,305,711  3,886,373  6,725,049  453  100% 
Prednisone  926  5,071,601  4,328,413  5,814,790  453  100% 
Hydralazine hydrochloride  671  5,038,406  3,892,650  6,184,161  453  100% 
Divalproex sodium  1,376  5,034,585  3,828,665  6,240,504  453  100% 
Sitagliptin phosphate  725  5,030,546  4,050,532  6,010,559  433  96% 
Meloxicam  812  4,961,315  3,941,103  5,981,528  453  100% 
Diltiazem hydrochloride  679  4,680,461  3,560,154  5,800,768  453  100% 
Lisinopril/hydrochlorothiazide  424  4,523,987  3,156,159  5,891,816  453  100% 
Risperidone  1,065  4,499,424  2,818,568  6,180,279  453  100% 
Lovastatin  436  4,474,108  3,137,442  5,810,774  452  100% 
Isosorbide mononitrate  617  4,433,861  3,172,550  5,695,171  453  100% 
Oxycodone  867  4,258,435  3,083,475  5,433,395  453  100% 
hydrochloride/acetaminophen 
Pregabalin  634  4,209,760  3,059,720  5,359,800  453  100% 
Losartan/hydrochlorothiazide  409  4,196,780  3,104,339  5,289,220  453  100% 
Baclofen  756  4,153,577  3,192,191  5,114,963  453  100% 
Latanoprost  728  4,152,578  3,393,595  4,911,561  453  100% 
Esomeprazole magnesium  614  4,106,582  3,259,331  4,953,832  365  81% 
Mirtazapine  1,073  4,083,960  3,336,113  4,831,806  453  100% 
Ibuprofen  657  4,067,142  3,310,197  4,824,087  453  100% 
 
 
Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2021 
OEI-05-21-00170  Appendix C | 24  The 200 drugs with the highest utilization by dual eligibles, continued 
Generic Name  Sample  Projected  95-Percent Confidence Interval  Number of  Percentage 
Size  Drug  Formularies  of 
Events  Including  Formularies 
Drug  Including 
Lower Bound  Upper Bound  Drug 
Donepezil hydrochloride  1,105  3,994,691  3,054,709  4,934,674  453  100% 
Diclofenac sodium  679  3,948,979  2,933,779  4,964,178  453  100% 
Atenolol  471  3,897,251  3,144,084  4,650,417  453  100% 
Insulin detemir  743  3,745,481  2,591,971  4,898,991  318  70% 
Insulin aspart  626  3,702,127  2,696,097  4,708,157  315  70% 
Cyclobenzaprine  547  3,701,331  2,741,016  4,661,647  453  100% 
hydrochloride 
Oxybutynin chloride  567  3,666,305  2,493,019  4,839,591  453  100% 
Lorazepam  958  3,647,683  2,921,958  4,373,407  453  100% 
Famotidine  833  3,609,674  2,855,735  4,363,612  453  100% 
Levetiracetam  803  3,536,946  2,654,103  4,419,789  453  100% 
Buspirone hydrochloride  608  3,428,445  2,231,218  4,625,673  453  100% 
Tizanidine hydrochloride  561  3,423,732  2,332,892  4,514,573  452  100% 
Rivaroxaban  555  3,259,590  2,384,089  4,135,092  446  98% 
Budesonide/formoterol  420  3,241,842  2,346,422  4,137,263  330  73% 
fumarate 
Memantine hydrochloride  1,044  3,144,442  2,443,810  3,845,073  453  100% 
Zolpidem tartrate  467  3,113,250  2,083,100  4,143,400  443  98% 
Naproxen  460  3,036,105  2,409,834  3,662,375  453  100% 
Venlafaxine hydrochloride  458  2,956,824  2,020,943  3,892,704  453  100% 
Paroxetine hydrochloride  415  2,894,034  1,991,599  3,796,470  453  100% 
Fluticasone  491  2,869,524  2,120,479  3,618,570  452  100% 
propion/salmeterol 
Lamotrigine  655  2,839,897  1,979,208  3,700,587  453  100% 
Apixaban  696  2,838,805  2,197,143  3,480,467  449  99% 
Oxycodone hydrochloride  456  2,824,439  2,111,379  3,537,498  452  100% 
Clonidine hydrochloride  489  2,806,732  2,019,967  3,593,496  453  100% 
Glimepiride  362  2,775,354  1,967,525  3,583,183  453  100% 
Topiramate  460  2,683,070  1,816,924  3,549,217  453  100% 
Spironolactone  460  2,673,655  2,002,489  3,344,821  453  100% 
Azithromycin  516  2,645,727  2,167,706  3,123,748  453  100% 
Olanzapine  658  2,612,191  1,540,447  3,683,936  453  100% 
Aripiprazole  591  2,533,246  1,784,392  3,282,100  453  100% 
Ropinirole hydrochloride  333  2,507,981  1,560,854  3,455,107  453  100% 
Insulin lispro  344  2,429,402  1,861,720  2,997,085  200  44% 
Alcohol antiseptic pads*  255  2,422,330  1,535,549  3,309,111  Supply Item    Supply Item 
 
Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2021 
OEI-05-21-00170  Appendix C | 25  The 200 drugs with the highest utilization by dual eligibles, continued 
Generic Name  Sample  Projected  95-Percent Confidence Interval  Number of  Percentage 
Size  Drug  Formularies  of 
Events  Including  Formularies 
Drug  Including 
Lower Bound  Upper Bound  Drug 
Valsartan  338  2,289,727  1,622,488  2,956,965  450  99% 
Polyethylene glycol 3350*  716  2,272,209  1,727,596  2,816,821  Excluded       Excluded 
Fluticasone/vilanterol  332  2,238,025  1,318,958  3,157,092  425  94% 
Nifedipine  324  2,167,546  1,331,366  3,003,726  451  100% 
Cephalexin  425  2,157,330  1,818,130  2,496,529  453  100% 
Benztropine mesylate  614  2,119,803  1,437,028  2,802,578  453  100% 
Pioglitazone hydrochloride  194  2,102,417  1,711,803  2,493,030  453  100% 
Finasteride  362  2,061,017  1,398,907  2,723,126  453  100% 
Amitriptyline hydrochloride  347  2,058,618  1,316,343  2,800,892  453  100% 
Diazepam  278  2,018,245  1,435,439  2,601,052  453  100% 
Tiotropium bromide  251  1,989,312  1,369,967  2,608,658  297  66% 
Celecoxib  265  1,923,378  1,257,384  2,589,373  436  96% 
Amoxicillin  424  1,912,429  1,610,851  2,214,007  453  100% 
Ciprofloxacin hydrochloride  421  1,910,739  1,674,779  2,146,699  453  100% 
Sulfamethoxazole/trimethoprim  455  1,902,153  1,624,159  2,180,147  453  100% 
Triamcinolone acetonide  340  1,823,720  1,483,571  2,163,868  453  100% 
Ezetimibe  192  1,741,807  1,102,083  2,381,531  453  100% 
Acetaminophen with codeine  361  1,710,452  1,338,958  2,081,946  453  100% 
Carbamazepine  399  1,710,047  1,107,813  2,312,280  453  100% 
Brimonidine tartrate  284  1,692,540  1,207,251  2,177,829  453  100% 
Ipratropium/albuterol sulfate  374  1,647,948  1,129,841  2,166,055  431  95% 
Sucralfate  245  1,630,572  1,056,470  2,204,675  453  100% 
Morphine sulfate  333  1,600,279  679,057  2,521,500  453  100% 
Fentanyl  255  1,591,038  966,177  2,215,899  453  100% 
Lactulose  404  1,587,102  1,024,068  2,150,136  453  100% 
Chlorthalidone  167  1,585,674  876,774  2,294,574  453  100% 
Cyclosporine  220  1,573,140  1,030,914  2,115,366  453  100% 
Linagliptin  295  1,571,344  927,047  2,215,642  359  79% 
Pramipexole di-hydrochloride  188  1,570,546  1,046,664  2,094,428  453  100% 
Timolol maleate  172  1,568,598  1,102,539  2,034,656  453  100% 
Digoxin  323  1,562,903  1,037,589  2,088,216  453  100% 
Amoxicillin/potassium clav  317  1,547,684  1,232,196  1,863,173  453  100% 
Propranolol hydrochloride  317  1,540,435  865,875  2,214,994  453  100% 
Sitagliptin phos/metformin  154  1,539,194  1,014,910  2,063,478  432  95% 
hydrochloride 
 
Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2021 
OEI-05-21-00170  Appendix C | 26  The 200 drugs with the highest utilization by dual eligibles, continued 
Generic Name  Sample  Projected  95-Percent Confidence Interval  Number of  Percentage 
Size  Drug  Formularies  of 
Events  Including  Formularies 
Drug  Including 
Lower Bound  Upper Bound  Drug 
Ketoconazole  364  1,537,124  1,129,720  1,944,528  453  100% 
Valsartan/hydrochlorothiazide  156  1,501,351  1,001,360  2,001,342  448  99% 
Meclizine hydrochloride  310  1,500,876  1,055,398  1,946,353  453  100% 
Enalapril maleate  115  1,476,000  828,752  2,123,248  453  100% 
Fenofibrate  213  1,460,807  817,304  2,104,309  452  100% 
Gemfibrozil  120  1,454,319  721,301  2,187,337  453  100% 
Olopatadine hydrochloride  233  1,439,133  1,119,506  1,758,761  431  95% 
Solifenacin succinate  224  1,430,873  763,888  2,097,857  342  75% 
Bimatoprost  191  1,422,244  923,431  1,921,056  429  95% 
Levofloxacin  315  1,416,217  1,139,333  1,693,100  453  100% 
Temazepam  215  1,406,177  847,474  1,964,880  418  92% 
Fenofibrate nanocrystallized  165  1,401,213  804,959  1,997,467  448  99% 
Dulaglutide  214  1,379,221  715,892  2,042,551  411  91% 
Doxycycline hyclate  280  1,348,381  1,058,266  1,638,496  452  100% 
Methylprednisolone  228  1,339,280  1,122,951  1,555,608  453  100% 
Doxazosin mesylate  195  1,336,241  739,025  1,933,456  453  100% 
Linaclotide  253  1,324,567  790,461  1,858,672  419  92% 
Dexlansoprazole  217  1,288,483  754,355  1,822,611  226  50% 
Verapamil hydrochloride  128  1,268,049  653,702  1,882,395  453  100% 
Insulin degludec  84  1,265,827  761,875  1,769,780  298  66% 
Omega-3 acid ethyl esters  123  1,251,856  772,322  1,731,391  345  76% 
Levocetirizine dihydrochloride  142  1,242,820  541,799  1,943,840  453  100% 
Promethazine hydrochloride  292  1,203,756  702,031  1,705,480  450  99% 
Triamterene/hydrochlorothiazid  131  1,201,873  653,212  1,750,534  453  100% 
Dicyclomine hydrochloride  181  1,191,989  666,466  1,717,512  453  100% 
Metoclopramide hydrochloride  201  1,186,831  555,336  1,818,326  453  100% 
Umeclidinium bromide  141  1,170,164  795,429  1,544,899  314  69% 
Torsemide  222  1,166,925  565,881  1,767,970  434  96% 
Fluconazole  237  1,155,400  877,134  1,433,666  453  100% 
Bumetanide  179  1,141,446  633,323  1,649,568  453  100% 
Lidocaine  197  1,138,762  659,494  1,618,030  453  100% 
Benazepril hydrochloride  153  1,135,052  729,076  1,541,027  452  100% 
Ramipril  144  1,126,063  647,924  1,604,202  453  100% 
Ondansetron hydrochloride  275  1,115,147  848,687  1,381,607  453  100% 
Dextroamphetamine/amphetamine  237  1,100,231  411,222  1,789,240  453  100% 
 
Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2021 
OEI-05-21-00170  Appendix C | 27  The 200 drugs with the highest utilization by dual eligibles, continued 
Generic Name  Sample  Projected  95-Percent Confidence Interval  Number of  Percentage 
Size  Drug  Formularies  of 
Events  Including  Formularies 
Drug  Including 
Lower Bound  Upper Bound  Drug 
Colchicine  184  1,082,482  475,136  1,689,828  453  100% 
Carbidopa/levodopa  312  1,072,686  557,328  1,588,044  453  100% 
Methotrexate sodium  126  1,053,620  440,553  1,666,687  453  100% 
Liraglutide  103  1,051,570  538,034  1,565,107  422  93% 
Mupirocin  221  1,028,462  710,526  1,346,398  453  100% 
Hydroxyzine hydrochloride  214  1,009,571  649,429  1,369,712  431  95% 
Ammonium lactate  182  1,007,852  653,393  1,362,310  453  100% 
Nitroglycerin  188  1,002,575  807,755  1,197,395  453  100% 
Ipratropium bromide  186  993,728  468,799  1,518,656  453  100% 
Ondansetron  225  985,202  657,129  1,313,276  453  100% 
Prazosin hydrochloride  53  953,109  510,678  1,395,541  453  100% 
Ranolazine  119  926,783  484,244  1,369,322  453  100% 
Haloperidol  227  916,058  461,131  1,370,985  453  100% 
Prednisolone acetate  136  897,900  578,153  1,217,647  453  100% 
Amiodarone hydrochloride  163  896,941  595,377  1,198,505  453  100% 
Doxepin hydrochloride  132  892,918  429,001  1,356,836  453  100% 
Metronidazole  164  885,694  651,846  1,119,541  453  100% 
Oxcarbazepine  243  885,091  502,053  1,268,130  453  100% 
Lacosamide  269  873,237  457,471  1,289,004  453  100% 
Chlorpromazine hydrochloride  82  872,727  330,681  1,414,773  453  100% 
Hydroxychloroquine sulfate  97  869,105  411,229  1,326,981  453  100% 
Dorzolamide  105  863,762  460,381  1,267,142  453  100% 
hydrochloride/timolol maleat 
Lubiprostone  225  849,124  489,606  1,208,643  223  49% 
Ergocalciferol (vitamin D )*  171  840,429  464,809  1,216,050  Excluded       Excluded 
2
Canagliflozin  95  831,706  286,521  1,376,890  196  43% 
Isosorbide dinitrate  106  820,865  425,940  1,215,790  453  100% 
Nitrofurantoin monohyd/m-cryst  176  814,269  617,527  1,011,011  443  98% 
Dapagliflozin propanediol  59  809,582  235,628  1,383,535  301  66% 
Valproic acid  107  809,352  289,961  1,328,743  453  100% 
Clozapine  284  782,771  270,037  1,295,504  453  100% 
Phenytoin sodium extended  107  763,138  340,031  1,186,244  453  100% 
Dabigatran etexilate mesylate  88  761,362  337,532  1,185,191  351  77% 
Empagliflozin  90  747,475  322,828  1,172,122  423  93% 
Buprenorphine  81  733,267  -28,179  1,494,713  Excluded     Excluded 
hydrochloride/naloxone 
hydrochloride* 
Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2021 
OEI-05-21-00170  Appendix C | 28   
The 200 drugs with the highest utilization by dual eligibles, continued 
Generic Name  Sample  Projected  95-Percent Confidence Interval  Number of  Percentage 
Size  Drug  Formularies  of 
Events  Including  Formularies 
Drug  Including 
Lower Bound  Upper Bound 
Drug 
Travoprost  179  729,170  502,768  955,573  362  80% 
Anastrozole  93  726,636  353,068  1,100,204  453  100% 
Brimonidine tartrate/timolol  151  725,204  461,848  988,560  412  91% 
Desvenlafaxine succinate  83  719,524  212,410  1,226,638  451  100% 
Source: OIG analysis of drugs commonly used by dual eligibles, 2021. Sample is from the 2018 MCBS.  Projections and confidence intervals are 
derived from its survey methodology. 
*Drugs excluded from the analysis. See Appendix D.   
 
 
 
Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2021 
OEI-05-21-00170  Appendix C | 29   
APPENDIX D 
 
Five drugs commonly used by dual eligibles were excluded from 
this analysis 
In 2021, five drugs commonly used by dual eligibles were excluded from this 
analysis. 
Generic Name  Reason Excluded From Analysis 
Alcohol antiseptic pads  Supply covered by Part D 
Polyethylene glycol 3350  Nonprescription drug not covered 
under Part D 
Ergocalciferol (vitamin D )  Vitamin or mineral product not 
2
covered under Part D 
Buprenorphine  Unable to confidently project use to 
hydrochloride/naloxone  entire dual-eligible population 
hydrochloride 
Ranitidine hydrochloride  Drug no longer offered 
Source: OIG analysis of formulary inclusion of drugs commonly used by dual eligibles, 2021.
Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2021 
OEI-05-21-00170  Appendix D | 30  APPENDIX E 
 
Rates at which prescription drug plan formularies associated 
with stand-alone Medicare Part D or Medicare Advantage plans 
include commonly used drugs, by region  
Inclusion of commonly used drugs by formularies associated with stand-alone 
Medicare Part D plans, by PDP region 
Across all 34 PDP regions, the rates of formularies inclusion of commonly used drugs 
ranged from 89 percent to 99 percent.  The average rate of inclusion was 96 percent 
for all PDP regions.  
Inclusion of commonly used drugs by formularies associated with Medicare 
Advantage plans, by MA-PD region 
Exhibit E-1: MA-PD formularies inclusion of commonly used drugs, by MA-PD region 
MA-PD  State(s)  Number  Average Rate  Minimum  Maximum 
Region*  of  of Drug  Rate  Rate 
 MA-PDs  Inclusion by 
Formularies 
1  Maine, New Hampshire  71  98%  97%  98% 
2  Connecticut, Massachusetts,  146  97%  92%  98% 
Rhode Island, Vermont 
3  New York  233  97%  92%  98% 
4  New Jersey  74  97%  90%  98% 
5  Delaware, the District of  50  98%  96%  98% 
Columbia, Maryland 
6  Pennsylvania, West Virginia  204  97%  90%  98% 
7  North Carolina, Virginia  197  98%  93%  99% 
8  Georgia, South Carolina  207  98%  95%  99% 
9  Florida  492  98%  90%  99% 
10  Alabama, Tennessee  171  98%  96%  100% 
11  Michigan  104  97%  95%  100% 
12  Ohio  168  97%  92%  100% 
13  Indiana, Kentucky  186  98%  95%  98% 
 
Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2021 
OEI-05-21-00170  Appendix E | 31  MA-PD formularies inclusion of commonly used drugs, by MA-PD region, continued
 
MA-PD  State(s)  Number  Average Rate  Minimum  Maximum 
Region*  of  of Drug  Rate  Rate 
 MA-PDs  Inclusion by 
Formularies 
14  Illinois, Wisconsin  225  97%  89%  100% 
15  Arkansas, Missouri  166  97%  90%  99% 
16  Louisiana, Mississippi  117  97%  95%  98% 
17  Texas  237  98%  92%  99% 
18  Kansas, Oklahoma  103  98%  96%  99% 
19  Iowa, Minnesota, Montana,  165  97%  92%  98% 
Nebraska, North Dakota, 
South Dakota, Wyoming 
20  Colorado, New Mexico  102  98%  92%  98% 
21  Arizona  113  97%  96%  98% 
22  Nevada  72  97%  94%  98% 
23  Idaho, Oregon, Utah,  290  98%  92%  100% 
Washington 
24  California  413  97%  93%  99% 
25  Hawaii  23  97%  92%  98% 
Source: OIG analysis of formularies inclusion of drugs commonly used by dual eligibles, 2021. 
* Region 26, which covers Alaska, had no MA-PDs available for 2021. 
Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2021 
OEI-05-21-00170  Appendix E | 32   
ACKNOWLEDGMENTS AND CONTACT 
 
Acknowledgments 
Lisa Minich served as the team leader for this study, and Jonathan Carroll served as 
the lead analyst.  Office of Evaluation and Inspections staff who provided support 
include Kevin Farber, Christine Moritz, and Kelsey Ridenour.  
This report was prepared under the direction of Laura Kordish, Regional Inspector 
General for Evaluation and Inspections in the Chicago regional office, and 
Adam Freeman, Deputy Regional Inspector General. 
Contact 
To obtain additional information concerning this report, contact the Office of Public 
Affairs at Public.Affairs@oig.hhs.gov.  OIG reports and other information can be found 
on the OIG website at oig.hhs.gov. 
Office of Inspector General 
U.S. Department of Health and Human Services 
330 Independence Avenue, SW 
Washington, DC 20201 
Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2021 
OEI-05-21-00170  Acknowledgments and Contact | 33   
ABOUT THE OFFICE OF INSPECTOR GENERAL 
 
 
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: 
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 audits help reduce waste, abuse, and mismanagement and promote economy 
and efficiency throughout HHS. 
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. 
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. 
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 OIGs 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. 
Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2021 
OEI-05-21-00170  About OIG | 34