Keywords: Emergency Department, Health Reform, Utilization, Impact, HCUP
We analyzed the relationship between the Affordable Care Act insurance coverage provisions and emergency department (ED) utilization rates, costs, and patient illness severity for different payer groups in states that did and did not expand Medicaid. We used the 2011-2014 Healthcare Cost and Utilization Project ED databases from 23 States (12 expansion and 11 nonexpansion) and estimated Poisson pseudo-maximum likelihood regressions with fixed effects for demographic groups, years, and States. We found that coverage expansion was associated with decreases in uninsured ED visit rates of more than 10 percent for females aged 19–34 years and 35–54 years and males aged 35–54 years. In non-expansion states, uninsured utilization rates remained unchanged or increased slightly. Changes in all-payer and private insurance rates were more muted and the size of the uninsured population eligible for coverage was strongly associated with changes in outcomes. Our findings may be of interest to State and Federal policymakers as well as hospitals and payers to improve and predict the impact of future coverage interventions on ED services.