When President Obama was selling his health care law one big claim he made is that expanding coverage would reduce expensive emergency room visits. The theory was people would instead get cheaper care at a regular doctor’s office. New research in the journal Science indicates this theory was completely wrong. From the abstract:

In 2008, Oregon initiated a limited expansion of a Medicaid program for uninsured, low-income adults, drawing names from a waiting list by lottery. This lottery created a rare opportunity to study the effects of Medicaid coverage using a randomized controlled design. Using the randomization provided by the lottery and emergency-department records from Portland-area hospitals, we study the emergency-department use of about 25,000 lottery participants over approximately 18 months after the lottery. We find that Medicaid coverage significantly increases overall emergency use by 0.41 visits per person, or 40 percent relative to an average of 1.02 visits per person in the control group. We find increases in emergency-department visits across a broad range of types of visits, conditions, and subgroups, including increases in visits for conditions that may be most readily treatable in primary care settings.

This was almost by accident a perfect natural experiment. The state didn’t have enough money to expand Medicaid to everyone so a lottery was used creating an ideal control group. Since conditions like this are unlikely to ever be recreated again studies of this population are likely to remain the gold standard for determining the impact of getting access to Medicaid.

It appears giving people low cost insurance makes them more likely to seek care of all types. If your goal is to reduce health care spending just giving people better financial access to care without changing the delivery system is not going to do it. This should not be too surprising. If someone is so worried about the cost of going to the hospital they end up dying prematurely at home it is counted as costing the system almost nothing.

Of course, if your goal is to promote quality of life and provide financial protection for regular people other studies have proven expanding Medicaid will do that very well.

Photo by Taber Andrew Bain, used under Creative Commons license