Medicaid expansion associated with no change in emergency department use across racial and ethnic groups

To estimate changes in the emergency department (ED) visit rate, hospitalization share of ED visits, and ED visit volumes associated with Medicaid expansion among Hispanic, Black, and White adults.

For the population of adults aged 26-64 with no insurance or Medicaid coverage, we obtained census population and ED visit counts during 2010-2018 in nine expansion and five nonexpansion states.

The primary outcome was the annual number of ED visits per 100 adults ("ED rate"). The secondary outcomes were the share of ED visits leading to hospitalization, total number ("volumes") of all ED visits, ED visits leading to discharge ("treat-and-release") and ED visits leading to hospitalization ("transfer-to-inpatient"), and the share of the study population with Medicaid ("Medicaid share").

An event-study difference in differences design that contrasts pre- versus post-expansion changes in outcomes in Medicaid expansion and nonexpansion states.

In 2013, the ED rate was 92.6, 34.4, and 59.2 ED visits among Black, Hispanic, and White adults, respectively. The expansion was associated with no change in ED rate in all three groups in each of the five post-expansion years. We found that expansion was associated with no change in the hospitalization share of ED visits and the volume of all ED visits, treat-and-release ED visits, and transfer-to-inpatient ED visits. The expansion was associated with an 11.7% annual increase (95% CI, 2.7%-21.2%) in the Medicaid share of Hispanic adults, but no significant change among Black adults (3.8%; 95% CI, -0.04% to 7.7%).

ACA Medicaid expansion was associated with no changes in the rate of ED visits among Black, Hispanic, and White adults. Expanding Medicaid eligibility may not change ED use, including among Black and Hispanic subgroups.