Do Changes in Health Insurance Coverage Explain Interstate Variation in Emergency Department Utilization?

Emergency department (ED) utilization has increased nationally, leading to overcrowding, which in turn increases wait times, adverse clinical outcomes, and costs. We constructed a state-level panel dataset of 50 U.S. states and the District of Columbia from 1999 to 2011 and used a first-differencing regression model to investigate the extent to which changes in public and private health insurance coverage could account for increased ED utilization. We found that changes in health insurance coverage explained some of the variations in ED utilization; however, the magnitudes of health insurance coverage variables were very small relative to the mean of ED utilization. This suggests that anticipated increases in private health insurance coverage and the Medicaid expansion due to the Affordable Care Act will not drive large changes in ED utilization.