The impact of Medicare Part D on Medicare-Medicaid Dual-eligible Beneficiaries' Prescription Utilization and Expenditures

Features of Part D gave rise to broad concern that the drug benefit would negatively impact prescription utilization among the six million dual eligible beneficiaries, either during the transition from state Medicaid to Part D coverage, or in the long-run. At the same time, Part D contained other features, such as its auto-enrollment and premium subsidization policies, which were designed to safeguard utilization for this vulnerable group. Using national retail pharmacy claims, we examine the experience of dual eligibles during the first 18 months of Part D. We find no evidence that Part D adversely affected pharmaceutical utilization or out-of-pocket expenditures in the transition period, or in the 18 months subsequent to Part D implementation.