Health care access, affordability, and satisfaction following enrollment in Medicare Advantage.

Introduction: Medicare Advantage (MA) enrollment is growing rapidly, yet less is known about how these plans impact health care access, affordability, and satisfaction for adults newly entering Medicare. Methods: Event study, difference-in-differences analysis comparing longitudinal changes in patient-reported outcomes among adults newly enrolled in MA (vs traditional Medicare [TM]) in the Health and Retirement Study (2010-2022). Results: There were 4247 adults who newly enrolled in Medicare between 65 and 67 years of age (34.2% MA; 65.8% TM). Following Medicare enrollment, health care access improved similarly in MA and TM, with no differential change between groups. However, MA enrollees experienced a greater reduction in the proportion of individuals reporting trouble affording medical care (difference-in-differences [DiD] estimate -5.3pp [95% CI, -9.7 to -0.9]). Additionally, the percentage of adults satisfied with their care increased for both groups; however, these gains were larger among MA enrollees and increased over time (DiD +13.3pp [95% CI, 7.9-18.6]). Conclusion: In this national, longitudinal study of adults entering Medicare, we found that enrollment in MA was associated with greater improvements in the affordability of care and higher satisfaction compared with enrollment in TM, without meaningful differences in health care access.