Racial and Ethnic Disparities Persist in Diabetes Drug Adherence

Black and Hispanic Medicare Advantage (MA) enrollees with diabetes were significantly less likely than White enrollees to adhere to guideline-recommended diabetes medications, according to a retrospective cohort study published in JAMA Network Open.

The study examined adherence to metformin, insulin, and sodium-glucose cotransporter 2 (SGLT2) inhibitors and/or glucagon-like peptide-1 receptor agonists (GLP-1 RAs) among MA enrollees with Part D coverage and a diabetes diagnosis, using a 20% national sample from 2019. Investigators sought to quantify disparities in adherence, defined as a proportion of days covered of at least 80%, and to identify individual-, plan-, and community-level factors associated with them.

The Black-White analysis included 80,586 Black and 233,505 White beneficiaries; the Hispanic-White analysis included 83,116 Hispanic and 190,509 White beneficiaries. In unadjusted analyses, adherence was lower among Black beneficiaries than White beneficiaries by 9.0 percentage points (pp) for SGLT2 inhibitors and/or GLP-1 RAs, 8.0 pp for insulin, and 10.5 pp for metformin (all P<0.001). Adherence gaps between Hispanic and White beneficiaries were 8.1 pp, 2.8 pp, and 3.6 pp, respectively (all P<0.001).

Differences between beneficiaries enrolled in the same plan, rather than differences between plans, accounted for most of the disparities: 74.6% to 85.3% of Black-White gaps and 39.1% to 66.1% of Hispanic-White gaps, depending on medication class. Enrollment in Medicaid or the Part D Low-Income Subsidy was associated with substantially reduced disparities in insulin and SGLT2 inhibitor/GLP-1 RA adherence, while plan-level characteristics and neighborhood socioeconomic status, measured by the Area Deprivation Index, explained smaller and more variable shares.

The authors noted that the study's observational design limits causal inference and that findings may not generalize beyond the three racial and ethnic groups analyzed. They concluded that additional insurance- and community-level strategies are needed to improve medication adherence among disadvantaged patients and communities.

Source: Essien UR, Roberts ET, Ruggiero DA, et al. Racial and ethnic disparities in medication adherence among Medicare Advantage enrollees with diabetes. JAMA Netw Open. 2026;9(9):e2634846. doi:10.1001/jamanetworkopen.2026.34846