Racial and Ethnic Differences in Potentially Inappropriate Medication Use Among Medicare Beneficiaries.

Importance: Older Medicare beneficiaries are susceptible to receiving potentially inappropriate medications (PIMs), where the risks outweigh the benefits. Racial and ethnic differences in PIM use may perpetuate health disparities and disproportionately lead to costly adverse drug events for some groups. Objective: To examine associations of race and ethnicity with PIM use among older Medicare beneficiaries. Design, Setting, and Participants: This cross-sectional study used nationwide Medicare Part D Event files, fee-for-service claims, and Medicare Advantage (MA) encounter data among Medicare beneficiaries 65 years or older with Part D prescription drug coverage. The study population included random samples of 20% of traditional Medicare (TM) beneficiaries and 50% of MA enrollees from January 1, 2016, to December 31, 2019. Analysis was conducted from May 28 to September 16, 2024. Exposure: Race and ethnicity. Main Outcomes and Measures: Linear probability models were estimated for outcomes of (1) high-risk medication use among older adults, (2) potentially harmful drug-disease interactions in patients with dementia, and (3) potentially harmful drug-disease interactions in patients with a history of falls. Results: The study sample included 21 193 170 patients with 32 199 587 beneficiary-year observations (mean [SD] age, 75.5 [7.3] years; 18 936 697 [58.8%] female; 983 513 [3.1%] Asian or Pacific Islander, 3 190 515 [9.9%] Black, 2 710 930 [8.4%] Hispanic, and 25 314 629 [78.6%] White). Compared with White beneficiaries, the rates of high-risk medication use were 1.7 [95% CI, -1.8 to -1.6] percentage points lower for Asian or Pacific Islander beneficiaries, 3.4 [95% CI, -3.4 to -3.3] percentage points lower for Black beneficiaries, and 0.6 [95% CI, -0.6 to -0.5] percentage points lower for Hispanic beneficiaries. Similarly, White beneficiaries had the highest rates of potentially harmful drug-disease interactions among those with dementia as well as those with a history of falls. The pattern of racial and ethnic differences was similar in analyses stratified by enrollment in TM or MA plans. However, the differences between White individuals and other groups were smaller in MA than in TM plans for all comparisons. Conclusions and Relevance: In this cross-sectional study of 32 199 587 Medicare beneficiary-years from 2016 to 2019, White Medicare beneficiaries had consistently higher rates of PIM use compared with other racial and ethnic groups. The observed differences may be partially explained by racial and ethnic differences in overall prescription drug use and suggest the need to reduce PIM use in all racial and ethnic groups.