Medicare part D and changes in prescription drug use and cost burden: national estimates for the Medicare population, 2000 to 2007.

CONTEXT The full effect of Medicare Part D, after the initial policy transition period and across the United States Medicare population, remains unclear. OBJECTIVE To estimate nationally representative changes in prescription drug use and out-of-pocket drug costs 2 years after implementation of Part D. DESIGN, SETTING, AND PARTICIPANTS We examined study outcomes over 8 years (2000 to 2007) and estimated changes after Part D, accounting for earlier trends. Our analyses used the community-dwelling sample of the Medicare Current Beneficiary Survey (unweighted unique n=38,798). Actual post-Part D outcomes were compared with projected values using 2000 to 2005 data. Subgroup analyses and standardization weights were used to address population-level shifts over time in health status and demographic characteristics. MAIN OUTCOME MEASURES Annual prescription drug fills and out-of-pocket drug costs. RESULTS We observed significant average per person increases of 1.8 prescription fills [95% confidence interval (CI), 1.1-2.5] in 2006 and 3.4 prescription fills (95% CI, 2.7-4.1) in 2007 above pre-Part D increases of 0.9 prescription fills per year. Average out-of-pocket drug costs decreased significantly by $143 (95% CI, -182.5--103.1) in 2006 and $148 (95% CI, -181.2--114.1) in 2007 above average pre-Part D increases of $12 per year. Prescription fills did not change for beneficiaries with fair to poor health until 2007 when large increases occurred (increases of 3.7 to 11.0 fills above pre-Part D trends). Significant reductions in OOP drug costs occurred in 2006 and persisted into 2007 across all groups except for sick and poor beneficiaries without Medicaid. CONCLUSIONS After the transition year of 2006, the impact of Part D seemed larger and more consistent across the Medicare population. Of note, sick and poor beneficiaries experienced significant improvements in prescription drug use in 2007.