The effect of Medicare Part D on prescription drug spending and health care use: 6 Years of follow-up, 2007-2012

Abstract

BACKGROUND: Previous studies have shown that Medicare Part D was associated with a reduction in out-of-pocket expenditures for Medicare beneficiaries during the early years of its implementation (2006 and 2007). However, a question remains regarding the effect of Part D on out-of-pocket expenditures in the longer term. OBJECTIVE: To evaluate the effects of Part D on prescription drug expenditures and certain health care use for a longer time period using a large, nationally representative sample of Medicare beneficiaries. METHODS: Using Medical Expenditure Panel Survey (MEPS) data from 2000 through 2005 (pre-Part D period) and from 2007 through 2012 (Part D era), this study identified a cohort of elderly Medicare beneficiaries (treatment group) and a near-elderly non-Medicare population (control group). A difference-in-differences analysis was conducted to estimate the effect of Part D on prescription medication use and expenditures and outpatient visits. Propensity score weights and sampling weights were applied to obtain unbiased effect estimates accounting for complex survey designs. RESULTS: A total of 26,585 elderly Medicare beneficiaries and 20,688 near-elderly non-Medicare beneficiaries were identified. The introduction of Part D was associated with an adjusted average reduction of $105 in annual out-of-pocket spending on prescription drugs during the post-Part D period (2007 through 2012). The reduction in annual out-of-pocket spending ranged from $49 to $152 during the post-Part D period. No significant increase was found in total prescription expenditures or prescription medication use following the introduction of Part D nor were there significant changes in outpatient visits. CONCLUSIONS: A continued reduction of Part D out-of-pocket drug expenditures was found each year from 2007 to 2012.