ED visits in California jump 9.9% after implementation of ACA

Proponents of the Affordable Care Act (ACA) argued—and continue to argue—that it will reduce frequent use of the emergency department (ED) by the same people with expanded coverage, especially for those most likely to make repeated visits to the ED.

Now, four years after several major expansion provisions of the ACA kicked in, researchers examined data from California to see just what impact the healthcare legislation had on ED usage.

The study—led by Shannon McConville, a senior research associate at the Public Policy Institute of California in San Francisco—was published online June 4 in Health Affairs.

“The likelihood of being a frequent ED user decreased in the two years following implementation of the major coverage provisions of the ACA,” the authors wrote. “Still, with the sizable increase in ED patients covered by state Medicaid programs and higher baseline odds of frequent ED use among Medicaid patients relative to those with other coverage, there has been an overall increase in both the share and the absolute number of ED patients who are frequent users.”

Some 20 million adults gained health insurance through the ACA, from the expansion of Medicaid and the private markets. But it remains unclear how this growth affected ED use. Would that many newly insured people increase utilization of EDs? Or would other available avenues of access reduce the need for emergency interventions?

The team conducted a retrospective analysis of data from 13.7 million patients in California’s Office of Statewide Health Planning and Development. Researchers examined ED visits during two periods—from 2012 and 2013 before ACA implementation and 2014 and 2015 after coverage expansions took effect. They identified a “frequent ED user” as someone who made four-plus visits in a single year. They also only restricted the population to 18- to-64-year-olds.

“In the two years after the ACA coverage expansions, the number of ED users increased by 511,284 (7.7 percent) compared to the two years before the expansions,” McConville and colleagues wrote. “And the number of ED visits increased by 1,155,772 (9.9 percent). The number of frequent ED users increased by 81,800 in the post-ACA period.”

Additional findings included:

  • In the pre-ACA period, 7.9 percent of ED patients were considered frequent visitors, compared to 8.5 percent of patients in the post-ACA period.
  • Medicaid patients represented 21.5 percent of visits in 2012-2013 and 37.6 in 2014-2015.
  • The rates of uninsured patients dropped from 26.9 percent pre-ACA to 13.2 post-ACA.
  • Frequent ED users who were covered by Medicaid jumped from 44.6 percent to 67.6 percent, while, among this same population, the uninsured rate dropped from 29 percent to 8.3 percent.

“[D]ifferences in the demographic characteristics of the total ED patient population and the frequent user population before and after the ACA were small, although nearly all were significant,” McConville et al. wrote. “After the ACA, both patient groups were slightly younger and had higher shares of Hispanic patients.”

After controlling for health status, insurance source and geographical differences, the team found the likelihood of patients being frequent ED visitors dropped after ACA implementation. While unable to draw a causal link, researchers emphasized how expanded coverage offered patients more avenues to access care.

“While our findings do not provide evidence that the ACA caused these changes, they suggest that expanded Medicaid coverage might have allowed patients to access needed medical services outside of the ED,” McConville et al. wrote. “This might have been especially true among people with chronic conditions who used the ED frequently pre-ACA but who became connected to a primary care provider as a result of the ACA Medicaid expansion via Medicaid managed care plans."