Effect of Medicare Part D on ethnoracial disparities in antidementia medication use

Objectives: To examine ethnoracial disparities in antidementia medication use, accounting for implementation of Part D, and to evaluate the role of prescription drug coverage as a cause of antidementia medication disparities. Design: Rotating panel of Medicare beneficiaries who participated in the Medicare Current Beneficiary Survey from 2003 to 2013. Setting: Nationally representative sample of Medicare fee-for-service (FFS) beneficiaries with dementia. Participants: Community-dwelling FFS Medicare beneficiaries with dementia (N=4,304). Measurements: Antidementia medication use, defined as at least one prescription fill in a given year. Results: Unadjusted antidementia medication use was 10–percentage points lower for ethnoracial minority beneficiaries before Part D was implemented in 2006 (p=.01). This difference was attenuated after adjusting for demographic and socioeconomic factors (6–percentage points; p=.10). Part D was associated with a 6–percentage point increase in use (p<.01). The increase in use associated with Part D was higher although not statistically significantly so in ethnoracial minority beneficiaries (8–percentage points, p=.08). Analyses of each ethnoracial group found a significant effect of Part D only in Hispanic/Latino beneficiaries (18–percentage points; p<.01, adjusted). Conclusion: Antidementia medication disparities were reduced with expanded prescription drug coverage through Medicare Part D. Increases in antidementia medication use for minority beneficiaries started after Part D was implemented, with the largest increases in use observed in Hispanic/Latino beneficiaries.