Zero-premium Medicare Advantage plans: trends in areas with socioeconomic vulnerability and health needs.

Introduction: Zero-premium Medicare Advantage (MA) plans are increasingly popular, yet knowledge gaps exist regarding their distribution, enrollment, and quality, particularly in areas with greater socioeconomic vulnerability and clinical need.

Methods: We conducted a serial cross-sectional study of publicly available CMS data from 2019-2024, analyzing 2472 US counties. Annual plan counts and enrollment rates were examined, stratified by county-level socioeconomic and health characteristics (racial/ethnic minority percentage, poverty rate, and prevalence of fair/poor health). Counties were categorized into quartiles for comparison.

Results: Zero-premium MA plans expanded substantially from 2019-2024, rising from 46.02% of MA plans (9.12 million enrollees) to 66.3% (18.76 million). These plans were more likely to feature restrictive provider networks and showed disproportionate enrollment growth in counties with greater socioeconomic and health needs (higher proportions of racial/ethnic minority residents, poverty, and poor health status; P < 0.001). Across all county-characteristic subgroups, zero-premium plans consistently had lower star ratings (1-3.5).

Conclusion: Rapid zero-premium MA plan adoption raises concerns about the quality of care, especially among vulnerable populations. Further examination of plan quality standards and patient outcomes, transparency of enrollment incentives (eg, insurance broker commissions), and enrollee navigation and decision-making about plan options is warranted.