Medicare Part D was expected to have differential impacts on patient drug expenditures and utilization based on beneficiaries’ levels of pre-Part D patient drug spending, but it is unknown whether these projections have borne out
We sought to evaluate whether and how the policy effect of Medicare Part D on drug expenditures and utilization was modified by levels of pre-Part D drug spending.
A quasi-experimental, pretest-posttest, nonequivalent control group design was used. Data were obtained from a regional supermarket chain for all prescriptions dispensed between January 1, 2005 and December 31, 2007 (n =1,230,612) to patients age 60 and older as of January 1, 2005 (n = 51,305) to construct 12-month pre-Part D and post-Part D periods. The treatment group was defined as individuals who were eligible via age, for Part D coverage on January 1, 2006 (ages 65+). The control group included individuals aged 60 through 62 on January 1, 2006. Annual medication utilization was measured as the total number of pill-days acquired. Annual drug expenditures were measured as total expenditures, patient out-of-pocket expenditures, and the proportion of total expenditures paid out of pocket by the patient.
Part D resulted in significantly greater reductions in absolute and relative out-of-pocket spending for individuals in the highest pre-Part D drug spending group relative to the moderate and low pre-Part D drug spending groups.
Our findings suggest that, as expected, Part D facilitated access to medications for patients who previously experienced the greatest costs without adversely increasing use and costs among those with the lowest prior cost.