First-time Medicare Advantage enrollees demonstrate increasing demographic and clinical diversity

To examine demographic and clinical characteristics of first-time Medicare Advantage (MA) enrollees between 2012 and 2022 and to better understand changes in this population as it has grown.

We used enrollment files and pharmacy claims from 2012 to 2022 to examine data from 5,075,279 MA beneficiaries with no prior enrollment in a large national health plan.

We descriptively examined annual rates of clinical severity (measured using the RxRisk-V Comorbidity Index) and patient demographics (race, age, sex, enrollment, and geographic characteristics). We used multivariate linear regression analyses to assess mean annual changes in clinical severity, controlling for demographic, geographic, and enrollment characteristics.

Results showed a rise in the share of dually eligible beneficiaries (from 13.0% to 23.0%), low-income subsidy recipients (from 19.4% to 27.0%), Special Needs Plan enrollees (from 2.6% to 14.8%), and Black beneficiaries (from 12.7% to 18.3%) from 2012 to 2022. MA enrollees who became Medicare eligible due to disability comprised 31.7% of the sample. We observed a small but statistically significant mean annual increase in the RxRisk-V Comorbidity Index score (0.021; 95% CI, 0.020-0.022; P < .0001), translating to a mean increase of 2 diagnoses per 100 beneficiaries each year.

In the past decade, the first-time MA enrollee population has become more demographically diverse and slightly more clinically complex. As MA enrollment continues to grow, policy makers and MA insurers should consider these trends in Medicare plan features, as enrollees may require additional social support. Designing Medicare benefits that align with the changing composition of the MA population is critical for addressing this population's health needs.