Effects of Medicare Part D medication therapy management on racial/ ethnic disparities in adherence to antidementia medications among patients with Alzheimer's disease and related dementias: An observational study

Background: Evidence is sparse on the effects of Medicare medication therapy management (MTM) on racial/ ethnic disparities in medication adherence among patients with Alzheimer's disease and related dementias. Objectives: This study examined the Medicare MTM program's effects on racial/ethnic disparities in the adherence to antidementia medications among patients with Alzheimer's disease and related dementias. Methods: This is a retrospective analysis of 100% of 2010-2017 Medicare Parts A, B, and D data linked to Area Health Resources Files. The study outcome was nonadherence to antidementia medications, and intervention was defined as new MTM enrollment in 2017. Propensity score matching was conducted to create intervention and comparison groups with comparable characteristics. A difference-in-differences model was employed with logistic regression, including interaction terms of dummy variables for the intervention group and racial/ethnic minorities. Results: Unadjusted comparisons revealed that Black, Hispanic, and Asian/Pacific Islander patients were more likely to be nonadherent than non-Hispanic White (White) patients in 2016. Differences in odds of nonadherence between Black and White patients among the intervention group were lower in 2017 than in 2016 by 27% (odds ratios [OR]: 0.73, 95% confidence interval [CI]: 0.65-0.82). A similar lowering was seen between Hispanic and White patients by 26% (OR: 0.74, 95% CI: 0.63-0.87). MTM enrollment was associated with reduced disparities in nonadherence for Black-White patients of 33% (OR: 0.67, 95% CI: 0.57-0.78) and Hispanic-White patients of 19% (OR: 0.81, 95% CI: 0.67-0.99). Discussion: The Medicare MTM program was associated with lower disparities in adherence to antidementia medications between Black and White patients, and between Hispanic and White patients in the population with Alzheimer's disease and related dementias. Conclusions: Expanding the MTM program may particularly benefit racial/ethnic minorities in Alzheimer's dis- ease and related dementia care.