Changes in Medicare Part D Plan Designs After the Inflation Reduction Act

Area of Science:

• Health Policy
• Pharmaceutical Economics
• Medicare Part D

Background:

• The Inflation Reduction Act (IRA) enacted significant changes to Medicare Part D prescription drug coverage starting in 2024 and 2025.
• These changes include an annual out-of-pocket spending limit of $2000 and a shift in financial responsibility from the government to plan sponsors.
• Federal policies aimed to prevent premium increases in 2025, potentially leading Part D plans to adjust deductibles and cost-sharing requirements.

Purpose of the Study:

• To quantify the annual changes in Medicare Part D premiums, deductibles, and medication cost-sharing.
• To analyze these changes across stand-alone and Medicare Advantage plans from 2019 to 2025.
• To assess the impact of the IRA on beneficiary out-of-pocket expenses.

Main Methods:

• A serial cross-sectional study design was employed, utilizing data from 2019 to 2025 for Medicare Part D enrollees.
• Primary outcomes included mean monthly premiums, annual deductibles, and the prevalence of coinsurance versus co-payments for various drug tiers.
• Mean monthly out-of-pocket costs for nine high-cost, non-specialty, brand-name medications were estimated and weighted by plan enrollment.

Main Results:

• Medicare Advantage plans saw deductibles decrease from 2019 to 2024 before rising to $228 in 2025. Coinsurance for preferred brand drugs increased significantly in 2025 (27.7%).
• Out-of-pocket costs for nine key drugs in Medicare Advantage plans rose to $73 monthly in 2025.
• Stand-alone Part D plans experienced a steady increase in deductibles to $490 and coinsurance for preferred brand drugs to 84.0% by 2025, with monthly drug costs reaching $108.

Conclusions:

• The implementation of the IRA's Part D changes in 2024-2025 coincided with plan design modifications that appear to increase beneficiary cost-sharing.
• These increases are particularly notable for individuals not exceeding the $2000 out-of-pocket limit and those enrolled in Medicare Advantage plans.
• Additional policy measures may be necessary to mitigate rising cost-sharing and ensure the affordability of essential Medicare Part D medications.