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Breaking News: The Real Scoop Behind the Oregon Health Study

Dark, Cedric MD, MPH

doi: 10.1097/01.EEM.0000444605.88959.56
Breaking News

Dr. Dark is an assistant professor of emergency medicine at Baylor College of Medicine. He is the founder and executive editor of the website Policy Prescriptions, which advocates for evidence-based health policy. Visit, @PolicyRx, and for more information.



The Oregon Health Insurance Experiment just published another installment, and the major finding won't surprise emergency physicians: Medicaid coverage results in a 40 percent increase in emergency department use.

Many of the health care pundits quickly sifted through the scientific results to support their opinions. Sarah Kliff reports the facts in the Washington Post (, Scott Gottlieb claims in Forbes that Medicaid fails the poor and the Affordable Care Act will fail the middle class ( while Avik Roy, also in Forbes, thinks the Oregon study undermines the rationale behind the ACA. ( Aaron Carroll reminds us in The Incidental Economist that more ED use isn't necessarily bad (, and Arthur Kellermann, MD, digs up a 20-year old New England Journal of Medicine paper explaining why Medicaid patients likely have to go to the ED in the first place instead of visiting a primary care doctor. (

Let's assimilate all this information in the context of the pre-existing Oregon results into what it all actually means for low-income Americans, EDs, and everyone else. The Oregon Health Insurance Experiment was a randomized trial of uninsured patients. ( Some were offered Medicaid via a lottery; others were not. The researchers reported the marginal effect of Medicaid. Here are six important findings from the most recent publication (Science 2014;343[6168]:263; with my interpretation in italics.

  • Medicaid does not have an effect on emergent, non-preventable conditions (e.g., heart attacks, trauma, etc.). EMTALA and EDs are doing a fine job of providing equal access to emergency care.
  • People without prior visits to the ED are most likely to increase their utilization once getting Medicaid. Medicaid won't exacerbate the ED frequent-flyer issue, but it will allow people to enter the health care system for the first time.
  • ED visits resulting in hospital admissions were unchanged. ED visits resulting in the patient being sent home increased. Medicaid prompts treatment for lower acuity conditions in the ED.
  • Medicaid increases the number of ED visits that primary care could treat by more than 50 percent. It appears that the primary care infrastructure is largely inadequate in Portland, as I suspect it is elsewhere in America.
  • The following were most likely to cause increased visits to the ED after Medicaid enrollment: chronic conditions, ambulatory sensitive conditions, headaches, and injuries. People are deferring treatment for acute injuries and for many issues that primary care could treat because they lack coverage.
  • ED visits went up by 0.41, from 1.02 per person (up 40%) while expenses went up $120 per person (up 28%). Individually that marginal ED visit doesn't seem to be that expensive (about $292) unless you compare it with a Medicaid PCP visit in Portland ($148 CPT 99205).


Prior results from the Oregon Experiment showed that overall hospital admissions went up 2.1 percent (so if ED admissions stayed the same, these are presumably elective admissions or maybe the unicorn-like “direct admission”), prescription drug use increased 15 percent, outpatient office visits increased 35 percent, and screenings increased, all while financial strain and depression decreased by about nine percent.

Clinical outcomes like HbA1C, cholesterol levels, blood pressure, and mortality, on the other hand, were not significantly changed. Patients in the Oregon study tended to be fairly healthy and the follow-up time was relatively short, so the power to detect short-term differences in clinical outcomes was extremely low.

What does all this mean?

People receiving Medicaid have pent-up health needs for which they will seek treatment. Primary care visits might go up 35 percent, ED visits might go up 40 percent, and health care costs will certainly go up. But low-income people will have less financial difficulties resulting from medical bills. Whether actual health outcomes will change will likely take far longer than 18 months to figure out.

EDs stand to benefit if visits go up and the cost of providing that increased care is adequately covered by Medicaid reimbursements.

This study does not really provide a direct answer for everybody else on whether securing your neighbor's health coverage alters your own health at all, though the Institute of Medicine suggests that it does. (

Using the Oregon Studies as a guide, how will we gauge the success (or failure) of the Affordable Care Act's Medicaid expansion?

Enrollment numbers: Only 30 percent of those who won the lottery in Oregon actually received Medicaid. The ACA has to beat those uptake numbers if we are to consider it successful.

Increased access to services: I would recommend checking process measures like recommended screening tests to determine if new Medicaid enrollees are getting the services we want them to receive. Looking at ED visits, hospitalizations, and primary care visits doesn't actually tell us about what happens when the patient and doctor meet.

Debt collections: If Medicaid is successful, fewer people will have collections because of medical bills. It would be nice to see fewer bankruptcies, too (but the science does not yet support that).

That's what the Oregon Health Study has told us so far. No more, no less.

Many political pundits, however, will inappropriately use certain statistics to grade the Affordable Care Act in the coming months. Nobody should expect Medicaid to fix clinical outcomes by the time the 2016 presidential campaigns are in full swing. Health care costs won't magically go down. Science says neither of those things will happen. So, political pundits, don't even go there. Instead, let's just see if Medicaid is doing what Medicaid is supposed to do: providing coverage, increasing access, and protecting poor people from further financial ruin.

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