Abstract
OBJECTIVE: Using data on 5 years of postexpansion experience, we examined whether the coverage gains from Affordable Care Act Medicaid expansion among Black, Hispanic, and White individuals led to improvements in objective indicators of outpatient care adequacy and quality. RESEARCH DESIGN: For the population of adults aged 45-64 with no insurance or Medicaid coverage, we obtained data on census population and hospitalizations for ambulatory care sensitive conditions (ACSCs) during 2010-2018 in 14 expansion and 7 nonexpansion states. Our primary outcome was the percentage share of hospitalizations due to ACSC out of all hospitalizations ("ACSC share") among uninsured and Medicaid-covered patients. Secondary outcomes were the population rate of ACSC and all hospitalizations. We used multivariate regression models with an event-study difference-in-differences specification to estimate the change in the outcome measures associated with expansion in each of the 5 postexpansion years among Hispanic, Black, and White adults. PRINCIPAL FINDINGS: At baseline, ACSC share in the expansion states was 19.0%, 14.5%, and 14.3% among Black, Hispanic, and White adults. Over the 5 years after expansion, Medicaid expansion was associated with an annual reduction in ACSC share of 5.3% (95% CI, -7.4% to -3.1%) among Hispanic and 8.0% (95% CI, -11.3% to -4.5%) among White adults. Among Black adults, estimates were mixed and indicated either no change or a reduction in ACSC share. CONCLUSIONS: After Medicaid expansion, low-income Hispanic and White adults experienced a decrease in the proportion of potentially preventable hospitalizations out of all hospitalizations.