Turnover among new Medicare Advantage enrollees may be greater than perceived

To characterize the proportion of Medicare Advantage (MA) enrollees who switched insurers or disenrolled to traditional Medicare (TM) in the years immediately after first choosing to join an MA health plan.

Retrospective analysis using 2012-2017 Medicare enrollment data.

We studied enrollees who joined MA between 2012 and 2016 and identified all enrollees who changed insurers (switched insurance or disenrolled to TM) at least once between the start of enrollment and the end of the study period. We categorized each change as switching insurers or disenrollment to TM, and by whether the previous insurer had exited the market.

Among 6,520,169 new MA enrollees, 15.6% had changed insurance within 1 year after enrollment in MA and 49.2% had changed insurance by 5 years. More enrollees switched insurers rather than disenrolled, and most enrollees who changed insurers did not do so as a result of insurer exits.

New MA enrollees change insurers at a substantial rate when followed across multiple years. These changes may disincentivize insurers from investing in preventive care and chronic disease management and, as shown in several non-MA populations, may lead to discontinuities in care, increased expenditures, and inferior health outcomes.