Long-Term Stability of Coverage Among Michigan Medicaid Beneficiaries : A Cohort Study.

BACKGROUND: Medicaid, the primary source of insurance coverage for disadvantaged Americans, was originally designed as a temporary safety-net program. No studies have used long-run data to assess the recent use of the program by beneficiaries. OBJECTIVE: To assess patterns of short- and long-term enrollment among beneficiaries, using a 10-year longitudinal panel of Michigan Medicaid eligibility data. DESIGN: Primary analyses assessing trends in Medicaid enrollment among cohorts of existing and new beneficiaries. SETTING: Administrative records from Michigan Medicaid for the period 2011 to 2020. PARTICIPANTS: 3.97 million Medicaid beneficiaries. MEASUREMENTS: Short- and long-term enrollment in the program. RESULTS: The sample includes 3.97 million unique beneficiaries enrolled at some point between 2011 and 2020. Among a cohort of 1.23 million beneficiaries enrolled in 2011, over half (53%) were also enrolled in Medicaid in June 2020, spending, on average, two-thirds of that period (67%) on Medicaid. These beneficiaries, however, experienced substantial lapses in coverage, as only 25% were continuously enrolled throughout the period. Enrollment was less stable when assessed from the perspective of newly enrolled beneficiaries, of whom only 37% remained enrolled at the end of the study period. LIMITATION: Primary estimates from a single state. CONCLUSION: For many beneficiaries, Medicaid has served as their primary source of coverage for at least a decade. This pattern would justify increasing investments in the program to improve long-term health outcomes. PRIMARY FUNDING SOURCE: Self-funded.