Part D Senior Savings Model Final Evaluation, 2021 to 2023

The Medicare Prescription Drug Benefit Program (Part D) offers outpatient prescription drug coverage to Medicare beneficiaries. From 2021 to 2023, the Center for Medicare and Medicaid Innovation tested the effect of lower, predictable cost sharing for insulins via the Part D Senior Savings (PDSS) Model. PDSS-participating plans offered a maximum $35 copayment per monthly supply of each prescribed insulin to beneficiaries enrolled in these plans. In addition, PDSS-participating plans could elect two optional model components: (1) a narrower first risk corridor, made available in 2021 and 2022 and designed to help plans and the Centers for Medicare & Medicaid Services (CMS) share in any unanticipated profits or losses associated with the model test and (2) a Part D rewards and incentives (R&I) program, where plans could offer incentives to beneficiaries with diabetes or prediabetes for participation in various activities, including medication therapy management. This report presents findings of a mixed-methods evaluation of the three years of the model on various outcomes, including access to insulins, health outcomes, beneficiary costs, progression through the Part D benefit phases, and financial outcomes for plans, manufacturers, and CMS.

A separate Findings at a Glance document provides an infographic that summarizes evaluation results.