The Medicare Part D program provides an outpatient prescription drug benefit to older adults and people with long-term disabilities in Medicare who enroll in private plans, including stand-alone prescription drug plans (PDPs) to supplement traditional Medicare and Medicare Advantage prescription drug plans (MA-PDs) that include drug coverage and other Medicare-covered benefits. This analysis provides the latest data about Medicare Part D enrollment, premiums, and cost sharing in 2021 and trends over time, based on data from the Centers for Medicare & Medicaid services (CMS) Part D Enrollment, Benefit, Landscape, and Low Income Subsidy files.
"Part D enrollment in Medicare Advantage drug plans has increased over time, while enrollment in stand-alone prescription drug plans has decreased in recent years"
A total of 48 million people with Medicare are currently enrolled in plans that provide the Medicare Part D drug benefit, representing more than three-quarters (77%) of all Medicare beneficiaries. This total includes plans open to everyone with Medicare, including stand-alone PDPs and MA-PDs, and plans for specific populations, including retirees of a former employer or union and Medicare Advantage Special Needs Plans (SNPs). Over time, Part D enrollment in MA-PDs has increased, reflecting enrollment growth in Medicare Advantage plans overall, while enrollment in PDPs has decreased each year since 2019.
In 2021, half of all Part D enrollees are enrolled in stand-alone PDPs (50%), and the other half are in MA-PDs (50%), but a slightly larger number of enrollees are in MA-PDs (24.1 million) than in PDPs (23.9 million) (Figure 1, Table 1). (MA-PD enrollment includes Medicare Advantage HMOs, PPOs, private fee-for-service, and Medicare Savings Account plans, and other Medicare private plans, including Medicare-Medicaid plans, Cost plans, and PACE plans). Between 2020 and 2021, the number of MA-PD enrollees increased by 11%, while enrollment in PDPs decreased by 4%.