Coverage Disruptions and Transitions Across the ACA's Medicaid/Marketplace Income Cutoff

The Affordable Care Act takes a "patchwork" approach to expanding coverage: Medicaid covers individuals with incomes 138% of the federal poverty level (FPL) in expansion states, while subsidized Marketplace insurance is available to those above this income cutoff.

To characterize the magnitude of churning between Medicaid and Marketplace coverage and to examine the impact of the 138% FPL income cutoff on stability of coverage.

We measured the incidence of transitions between Medicaid and Marketplace coverage. Then, we used a differences-in-differences framework to compare insurance churning in Medicaid expansion and non-expansion states, before and after the ACA, among adults with incomes 100-200% of poverty.

Non-elderly adult respondents of the Medical Expenditure Panel Survey 2010-2018 MAIN MEASURES: The annual proportion of adults who (1) transitioned between Medicaid and Marketplace coverage; (2) experienced any coverage disruption.

One million U.S. adults transitioned between Medicaid and Marketplace coverage annually. The 138% FPL cutoff in expansion states was not associated with an increase in insurance churning among individuals with incomes close to the cutoff.

Transitions between Medicaid and Marketplace insurance are uncommon-far lower than pre-ACA analyses predicted. The 138% income cutoff does not to contribute significantly to insurance disruptions.