Skip to main content

ED Use Remains High Despite Medicaid Expansion in Oregon

October 21, 2016

Despite the expansion of Medicaid under the Affordable Care Act (ACA), offering enrollees more care options, recent data demonstrated that Oregon’s Medicaid beneficiaries continue to visit emergency departments (ED) as primary care two years after the expansion program launched.

In 2008, Oregon selected potential enrollees on a waiting list through a randomized-lottery system. The state drew names at random from a waiting list of approximately 90,000 for 10,000 available Medicaid slots during eight separate lottery draws from March 2008 through September 2008. Those selected were able to apply for a Oregon Health Plan Standard and, if found eligible, to enroll.

Amy N Finkelstein, PhD, of the department of economics at the Massachusetts Institute of Technology, and colleagues studied the impact of this Medicaid lottery program on ED utilization in Oregon. Researchers analyzed data between 2007 through 2010, specifically focusing on the pattern of the effect of Medicaid coverage on ED use over a 2-year period after the launch of the lottery.

The researcher’s findings, reported in The New England Journal of Medicine, found that ED visits increased by 40% in the first 15 months after expansion under the lottery program. According to the study, it was believed that ED utilization would lessen over time as the newly insured found alternative sites of care. They found that Medicaid coverage increased the mean number of ED visits per person by 0.17 (standard error, 0.04) over the first 6 months or about 65% relative to the mean in the control group of individuals not selected in the lottery.


U.S. Govt Sees 1 Mln More People on Obamacare Exchanges in 2017
UnitedHealth Sees More Growth in 2017 When it Exits Obamacare

“[We] found no evidence that the increase in ED use due to Medicaid coverage is driven by pent-up demand that dissipates over time; the effect on ED use appears to persist over the first 2 years of coverage,” Dr Finkelstein and colleagues wrote. “We repeated a similar analysis for hospital admissions and once again found no evidence of any time patterns in the effects of Medicaid coverage over the first 2 years.”

Dr Finkelstein and colleagues noted that prior researcher revealed Medicaid increased both physician office visits and ED use. That research was based on annual office visits from a 2010 survey, combined with administrative ED records for the same people over 12 months to see if a correlation existed between office visits and ED use through Medicaid. There was no evidence that Medicaid coverage makes use of the physician’s office and use of the ED more substitutable for each other; instead, the results suggested that the two are complementary.

“For policymakers deliberating about Medicaid expansions, our results, which draw on the strength of a randomized, controlled design, suggest that newly insured people will most likely use more health care across settings — including the ED and the hospital — for at least 2 years and that expanded coverage is unlikely to drive substantial substitution of office visits for ED use,” Dr Finkelstein and colleagues concluded.

Julie Gould



Finkelstein AN, Taubman SL, Allen HL, Wright BJ, Baicker K. Effect of Medicaid Coverage on ED Use — Further Evidence from Oregon’s Experiment [published online October 20, 2016]. N Engl J Med. 2016;375:1505-1507. DOI: 10.1056/NEJMp1609533.

Back to Top