Medicaid expansion and resource utilization in the emergency department

The Affordable Care Act (ACA) has impacted the insurance mix of emergency department (ED) visits, yet the degree to which this has influenced provider behavior is not clear.

This was a difference-in-differences (DID) analysis of ED-visit data from five states in 2013 and 2014. Sample states included 3 expanding Medicaid under the ACA, 1 rejecting ACA funding and delaying an eligibility expansion, and 1 with no eligibility change. We included self-pay and Medicaid patients aged 27 to 64 years. A subsample analysis was done for chest pain visits. DID logistic models were estimated for likelihood of admission for given Medicaid-paid ED visits in expansion states as compared to non-expansion states. Among chest pain visits we assessed likelihood given visits resulted in admission or advanced cardiac imaging, where clinician discretion may be more significant.

A total of 8,157,748 ED visits with primary payer Medicaid and self-pay were included, of which 331,422 were for chest pain. The proportion of visits paid for by Medicaid rose in expansion states by between 15.8% and 38.9%. Medicaid eligibility expansion was associated with increased odds of admission (OR 1.070 [95% CI 1.051-1.089]). Among chest pain visits, expansion was associated with increased odds of admission (OR 1.294 [95% CI 1.144-1.464]), but not advanced cardiac imaging (OR 1.099 [95% CI 0.983-1.229]).

Medicaid expansion was associated with small increases in ED visit admissions across the board and among the subgroup of patients presenting with chest pain.