An Overview of Medicare Part D Enrollment, Costs in 2024

Jul 18
Jul 18, 2024

Medicare Advantage Prescription Drug plans (MA-PDs) continued to gain more enrollees than stand-alone Prescription Drug Plans (PDPs) in 2024, according to a KFF analysis.

As of 2024, about 53.1 million Medicare beneficiaries were enrolled in a plan with Part D prescription drug coverage, with 57% in MA-PDs and 43% in stand-alone PDPs. Two-thirds of enrollees receiving the low-income subsidies (LIS) — 9 million out of 13.7 million — chose MA-PDs in 2024. Among the 14 national PDPs, 11 of them lost non-LIS enrollees, with only Wellcare Value Script seeing significant membership growth (from 2.6 million to 3.7 million) due to its low monthly premium.

According to AIS’s Directory of Health Plans, the four largest PDP insurers by market share — Centene Corp., UnitedHealth Group, Cigna Healthcare and Humana Inc. — accounted for almost 90% of enrollment as of the first quarter of 2024. Centene reported year-over-year membership growth of nearly 45.7%, while Humana saw a double-digit loss at 22.7%.

The average monthly premium for PDPs was nearly five times higher than MA-PDs in 2024: $43 vs. $9, according to KFF. The difference between premiums for drug coverage offered by PDPs and MA-PDs has grown larger in recent years, as the MA-PD sponsors can allocate some of the rebate dollars from Medicare payments to lower or eliminate their Part D premiums.

In 2024, three-fourths of MA-PD enrollees without LIS paid no premium for their drug coverage, yet over half of PDP enrollees without LIS paid $30 or more. Among the 14 national PDPs, 12 saw their average monthly premiums go up, while seven of them — with a combined 3.4 million non-LIS enrollees — reported increases of more than $10.

In addition, PDP enrollees were more likely than MA-PD enrollees to pay coinsurance — a percentage of a drug’s price — for preferred brands and non-preferred drugs in 2024. Yet MA-PD enrollees faced higher median coinsurance for specialty drugs.
© 2024 MMIT

Jinghong Chen

Jinghong has been producing infographics and data stories on employer-sponsored insurance, public health insurance programs and prescription drug coverage for AIS Health’s Health Plan Weekly and Radar on Drug Benefits since 2018. She also manages AIS Health’s annual executive compensation database for top insurers and Blue Cross and Blue Shield affiliates. Before joining AIS Health, she interned at WBEZ, Al Jazeera English and The New York Times Chinese. She graduated from Missouri School of Journalism with a focus on data journalism and international reporting.