Differences in Racial and Ethnic Responses to Medicaid Expansion Under the Affordable Care Act

Recent research indicates that non-white adults have benefitted disproportionately from expansion of Medicaid eligibility under the Affordable Care Act (ACA), which has led to reductions in racial and ethnic disparities for health care coverage. These population-level findings, however, may mask racial and ethnic differences that persist within the Medicaid-eligible sub-population, given evidence that the transaction costs and barriers involved in responding to coverage expansions may differ across racial and ethnic groups. The decision by many states not to expand Medicaid eligibility following implementation of the ACA provides a quasi-experimental opportunity to test the association between expansion and changes in racial and ethnic disparities in coverage and access to care among Medicaid-eligible individuals.

We used individual-level data from the Behavioral Risk Factor Surveillance System (BRFSS) survey for 2011-2014 to estimate the effect of state expansion of Medicaid eligibility on four measures of health care access: having insurance coverage, having a personal doctor, avoiding care due to cost, and having a checkup within the last year. We used a triple differences design in which we compared health care access before and after Medicaid expansion (January 1, 2014), in states that did and did not expand, across white, black, and Hispanic individuals. We limited our analysis to individuals aged 25 to 64 who were either eligible for Medicaid according to 2014 state-specific standards or had an income under 138 percent of the federal poverty level (FPL). The latter criterion ensured that our analysis involved comparisons of similar individuals across all states and years. Our main specification excluded individuals who responded to BRFSS within three months before and after Medicaid expansion in their respective states. We conducted a number of robustness checks in which we altered the size of this bandwidth. We also performed placebo tests in which we limited our analysis to respondents over age 65 or with income greater than 400 percent of the FPL, two groups for whom we expected the effects of Medicaid expansion to be greatly attenuated.

We found Medicaid expansion under the ACA was associated with an 8-percent increase in the health insurance coverage disparity between Hispanic and white low-income individuals residing in expansion states (p<0.05). We found no other significant changes in disparities for access to care between Hispanic and white adults or black and white adults using our main specification. This finding suggests that racial and ethnic groups may respond differentially to expansion of insurance coverage. Disparities within the Medicaid-eligible sub-population could increase without targeted efforts to address group-specific barriers to take-up of coverage.