Medicare Advantage and Type 2 Diabetes Outcomes.

Abstract

Importance: Medicare Advantage (MA) costs 22% more than original Medicare (OM) for a given individual ($83 billion in annual excess public costs). However, MA may improve type 2 diabetes (T2D) outcomes compared with OM by providing financial protections (eg, annual out-of-pocket spending caps) and supplemental benefits (eg, healthy food assistance) that OM cannot.

Objective: To determine whether MA coverage is associated with better T2D outcomes than OM.

Design, setting, and participants: A longitudinal cohort study using target trial emulation principles for design and analysis in adults aged 18 years or older receiving OM or MA with T2D, followed up before and after Medicare coverage in community-based health centers (January 2021 to June 2024) across 44 states. Analyses were conducted from September 2025 to May 2026.

Exposures: MA or OM coverage.

Main outcomes and measures: Hemoglobin A1c (HbA1c) (primary outcome), systolic blood pressure (SBP) and diastolic blood pressure (DBP), low-density lipoprotein (LDL) cholesterol, food insecurity, housing instability, and transportation barriers at 12 months after Medicare coverage (primary time point) and at 6, 18, and 24 months. Statistical analysis accounted for pre-Medicare coverage factors that may influence selection of MA vs OM using targeted minimum loss estimation. Covariates were age, sex, race and ethnicity, comorbidities, income, Social Vulnerability Index, pre-Medicare insurance, Medicaid coverage, and pre-Medicare coverage values for HbA1c, SBP, DBP, LDL cholesterol, body mass index, food insecurity, housing instability, and transportation barriers.

Results: In this study in 34 648 adults (19 054 in OM, 15 594 in MA) with T2D, followed up before and after Medicare coverage, the mean (SD) age was 65.24 (9.73) years and 53.42% were women. Twelve months after Medicare coverage, MA was not associated with better HbA1c (mean difference, 0.01; 95% CI, -0.04 to 0.05, P = .74), SBP (-0.15; 95% CI, -0.54 to 0.24; P = .44), DBP (0.06; 95% CI, -0.15 to 0.27; P = .58), or LDL cholesterol (-0.41; 95% CI, -1.24 to 0.42; P = .33), with similar results at other time points. MA was also not associated with a lower risk of food insecurity (relative risk [RR], 1.00; 95% CI, 0.94-1.05), housing instability (RR, 1.00; 95% CI, 0.91-1.09), or transportation barriers (RR, 1.00; 95% CI, 0.93-1.07) at 12 months or any other time point.

Conclusions and relevance: In this study, when accounting for factors that may drive MA selection, MA was not associated with better T2D outcomes or fewer health-related social needs than OM. Given substantially higher spending for MA, it is important to ensure this spending is being used effectively to improve health.