Article Title

Emergency Department Use in Alameda County, California, Before and After the Implementation of the Coverage Provisions of the Affordable Care Act

Publication Date



Affordable Care Act, emergency department overcrowding


Background/Aims: Hospital emergency departments (EDs) across the United States struggle with overcrowding, a problem reported to be associated with decline in quality of care and patient satisfaction, decreased revenue and increased patient mortality. The 2010 Affordable Care Act (ACA), upon its full implementation on Jan. 1, 2014, extended health coverage to 32 million Americans. Initial studies have reported a rise in ED utilization post-ACA, but no formal analysis has been conducted in the Sutter Health system. We sought to characterize the change in ED use at two Sutter Health hospitals before and after ACA.

Methods: We reviewed demographic and hospital accounts data from California’s Office of Statewide Health Planning and Development (OSHPD) as well as electronic health records for patients at two Sutter Health hospitals in Alameda County, California. We compared utilization and health care costs during comparable 6-month periods before and after the ACA expansion, and also examined trends over time from 2010 to 2014.

Results: From 2010 to 2013, encounters from OSHPD not resulting in a hospital admission were steady at the two hospitals; in 2014, they rose by 9%. This was comprised of a 2% increase in commercial, 44% increase in Medicaid and 32% decrease in self-pay encounters. From records comparing the last 6 months of 2013 to the last 6 months of 2014, total encounters rose by 11%. While there were 3,143 fewer encounters by uninsured individuals, there were 7,478 more encounters by the insured (including individuals with Medicare, Medicaid and commercial). Charges increased by 20% (commercial 29%, Medicaid 59%, Medicare 23%, self-pay -52%) between the time periods.

Conclusion: ED use at the two hospitals increased after the implementation of the ACA’s coverage expansions. The jump in aggregate ED visits came after at least three years of relatively stable ED use and was attributable to a shift in uninsured patients gaining Medicaid or commercial insurance coverage. Further research is required to determine the mechanism behind the increased utilization specific to insurance type and the possible implications for this extra burden on an already overcrowded ED.




June 30th, 2016


August 12th, 2016