Waiving Part D Drug Copays Improves Medication Adherence, Report Shows

Removing Medicare Part D copay amounts for low-income beneficiaries significantly enhanced medication adherence, according to a Wakely report. As the CMS Center for Medicare and Medicaid Innovation ends the Value-Based Insurance Design (VBID) model later this year, these findings highlight the “compelling need for both state and federal policymakers to explore new strategies or incentives that enable MAOs to continue offering similar benefits” and improve outcomes to members with specific socioeconomic statuses, Wakely observed.

Beginning in 2021, Medicare Advantage plans were allowed to waive Part D cost-sharing amounts for select members through the VBID model. As of 2025, 62 MA organizations are offering that benefit for their Dual Eligible Special Needs Plan (D-SNP) members. D-SNP members who were eligible for the benefit had $0 copays on all covered drugs, through all phases of coverage.

The Wakely report studied eight D-SNP plans with more than 70,000 members that began waiving Part D copays in 2023. It found that the average medication adherence among people taking medications for diabetes, hypertension (renin-angiotensin system antagonists) and cholesterol (statins) improved after their plans implemented the copay waiver. The study gauged medication adherence based on how plans scored on that measure in the MA Star Ratings program.

MA beneficiaries between 65 and 69 years old who had diabetes saw the most significant improvement in medication adherence, with an increase of 6.9% between 2022 and 2023, according to the report. Meanwhile, enrollees aged 70 and older demonstrated negative changes in medication adherence for cholesterol.

The researchers also used beneficiaries’ risk scores to examine how health status played a role in medication access and adherence. MA enrollees with higher risk scores — people who have one or more risk factors associated with diabetes, hypertension or high cholesterol — showed slightly greater improvements in adherence to diabetes medications than enrollees with lower risk scores following the cost-sharing waiver implementation. Enrollees taking hypertension and cholesterol treatments who had lower risk scores exhibited larger increases in adherence than those with 2.0 or higher risk scores.

CMS will terminate the VBID model at the end of 2025 due to its “substantial and unmitigable costs to the Medicare Trust Funds.” To continue offering $0 cost share for a subset of drugs, Wakely suggested that MA plans in 2026 may shift from a defined standard to enhanced alternative plan type and use tiered formulary designs for their D-SNPs.

This infographic was reprinted from AIS Health’s biweekly publication Radar on Drug Benefits.