Closing Gaps or Holding Steady? The Affordable Care Act, Medicaid Expansion, & Racial Disparities in Coverage, 2010-2021.

Context: The Affordable Care Act's (ACA) Medicaid expansion produced major gains in coverage. However, findings on racial and ethnic disparities are mixed and may depend on how disparities are measured. This study examines both absolute and relative changes in uninsurance from 2010-2021 by race and ethnicity, stratified by Medicaid expansion status.

Methods: The sample contained all respondents under age 65 (N = 30,339,104) from the American Community Survey, 2010-2021. Absolute and relative differences in uninsurance, compared to White Non-Hispanic individuals, were calculated for Hispanic; Black; Asian-American, Pacific Islander and Native Hawaiian (AANHPI); American Indian and Alaska Native (AIAN); and multiracial individuals. States were stratified into ever-expanded vs. non-expansion status.

Findings: After the ACA, three patterns of coverage disparities emerge. For Hispanic and Black individuals, relative to White individuals, absolute disparities in uninsurance declined but relative disparities were largely unchanged, in both expansion and non-expansion states. For AANHPI individuals, disparities were eliminated entirely in both expansion and non-expansion states. For AIAN individuals, disparities declined in absolute terms but grew in relative terms, particularly in expansion states.

Conclusions: All groups experienced coverage gains post-ACA, but with heterogeneity in changes in disparities. Focused interventions are needed to improve coverage rates for Black, Hispanic, and AIAN individuals.