BACKGROUND/OBJECTIVES Clinical practice guidelines support using acetylcholinesterase inhibitors (AChEIs) and memantine to treat dementia, but conflicting evidence of effectiveness and frequent side effects limit use in practice. We examined racial/ethnic differences in initiation and time to discontinuation of antidementia medication in Medicare beneficiaries. DESIGN Retrospective cohort study. SETTING Secondary analysis of 2009/2010 enrollment, claims, and Part D prescription data for a 10% national sample of U.S. Medicare fee-for-service enrollees. PARTICIPANTS Beneficiaries aged 65+ with Alzheimer's Disease or Related Disorder (ADRD) prior to 2009 and no fills for antidementia medications in the first half of 2009 (n=84,043). MEASUREMENTS Initiation was defined as having ≥1 fill for antidementia medication in the second half of 2009, and discontinuation as a gap in coverage of ≥30 days during one year after initiation. Covariate selection was guided by the Andersen Behavioral Model. RESULTS Overall, 3,481 (4.1%) of previous non-users initiated antidementia medication in the second half of 2009. Of those initiating one drug class (AChEIs or memantine), 9% later added the other class and 2% switched classes. Among initiators, 23% discontinued within one month and 62% discontinued within one year. Hispanic beneficiaries were more likely than White beneficiaries to initiate (adjusted odds ratio [OR]=1.25, 95% CI=1.10-1.41). Black and White beneficiaries did not differ in likelihood of initiation. Hispanic and Black beneficiaries discontinued at a faster rate than White beneficiaries (adjusted hazard ratio [HR]=1.56, 95% CI=1.34-1.82 and HR=1.25, 95% CI=1.08-1.44, respectively). CONCLUSION Relative to White beneficiaries, initiation of antidementia medications was no different in Black beneficiaries and more likely in Hispanic beneficiaries. However, Black and Hispanic beneficiaries discontinued at a faster rate. More research into reasons explaining these differences is needed.

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