Does an expansion of health insurance increase or decrease use of the emergency department (ED)? Both predictions can be justified logically. On the one hand, research on patient cost sharing predicts that by reducing the out-of-pocket costs of an ED visit, expanded insurance coverage, especially in the face of physician shortages, could result in increased ED utilization. This view has been echoed by elected leaders: Senator Jon Kyl (R-AZ), citing the Massachusetts experience with health care reform, claimed that if anything, universal coverage brought even higher rates of emergency room visits due to increased difficulty in getting appointments for outpatient physician visits. Others have predicted that expanded coverage would actually reduce ED use, since previously uninsured patients would now have access to preventive care. The relative importance of these countervailing forces is a question that clearly weighs on physicians: in a survey of emergency physicians conducted in April 2010, about 71% said they expected emergency visits to increase after the passage of the Affordable Care Act (ACA). To explore the importance of these effects, we examined the Massachusetts experience. The state's 2006 health care reform was a model for the ACA and reduced the proportion of Massachusetts adults under the age of 65 who were uninsured by 7.7 percentage points between the fall of 2006 and the fall of 2009. To determine whether any changes in ED utilization in Massachusetts reflected the effect of Massachusetts' reform or were merely representative of broader regional trends in ED utilization, we used New Hampshire and Vermont as control states.
Chen, Christopher, Gabriel Scheffler, and Amitabh Chandra. "Massachusetts' Health Care Reform and Emergency Department Utilization." New England Journal of Medicine 365.12 (September 22, 2011).