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Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2018


This report fulfills for 2018 the annual reporting mandate from the Patient Protection and Affordable Care Act (ACA). The ACA requires OIG to conduct a study of the extent to which formularies used by Medicare Part D plans include drugs commonly used by full benefit dual eligible individuals (i.e., individuals who are eligible for both Medicare and full Medicaid benefits). These individuals generally get drug coverage through Medicare Part D. Pursuant to the ACA, OIG must annually issue a report with recommendations as appropriate. This is the seventh report the OIG has produced to meet this mandate.


For this report, we determined whether the 386 unique formularies used by the 3,476 Part D plans operating in 2018 cover the 200 drugs most commonly used by dual eligibles. We also determined the extent to which plan formularies applied utilization management tools to those commonly used drugs. To create the list of the 200 drugs most commonly used by dual eligibles, we used the 2013 Medicare Current Beneficiary Survey-the most recent data available at the time of our study. Of the top 200 drugs, 197 are eligible for Part D prescription drug coverage, 2 are excluded from coverage and 1 is a Part D covered medical supply item.


Overall, we found that the rate of Part D plan formularies' inclusion of the 197 drugs commonly used by dual eligibles is high, with some variation. On average, Part D plan formularies include 96 percent of the 197 commonly used drugs. In addition, 68 percent of the commonly used drugs are included by all Part D plan formularies. These results are largely unchanged from OIG's findings for formularies reported in the mandated annual report from 2017, as well as our findings from 2011 through 2016.

We also found that the percentage of drugs to which plan formularies applied utilization management tools increased slightly between 2017 and 2018. On average, formularies applied utilization management tools to 29 percent of the unique drugs we reviewed in 2018, an increase of 1 percentage point from 2018.


Inclusion rates for the 197 drugs commonly used by dual eligibles are largely unchanged compared with the inclusion rates listed in our previous reports. Part D formularies include roughly the same high percentage of these commonly used drugs in 2018 as they did in 2017. 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 commonly use. In addition, OIG will continue to monitor Part D plan formularies' application of utilization management tools to these drugs. OIG has no recommendations at this time.