A lynchpin of the argument in favor of the Affordable Care Act is that increasing coverage will decrease the use of emergency rooms for care for lower income individuals.  However, a study published in Science magazine reports that this may not be true.  The research was conducted in 2008 in Oregon, where a limited expansion of Medicaid for low-income adults was available.  There was a lottery conducted to offer coverage to those that did not have it.

Over approximately 18 months after the lottery, data was collected from Portland-area hospitals.  Specifically, data was gathered on the use of the emergency department by 25,000 lottery participants.  They found that Medicaid coverage significantly increased overall emergency use by 0.41 visits per person, or 40 percent in comparison to a control group.  This trend persisted even when considered 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.

According to ABC News Radio, the study author noted that emergency room services can be less expensive than going through primary care.  Thus, normal economic principles mean that people will use more of the service that costs them less than the one that could cost more.  They may also be more familiar with that type of service.  Additionally, this study only covered 18 months and there may be a pronounced shift towards primary care as people understand how to optimize their use of benefits.  A longer-term study in Massachusetts, which expanded coverage for its residents in 2006, found an 8 percent decline in emergency department use over a period of several years.

However, the New York Times points out that, for now, the findings cast doubt on the hope that expanded insurance coverage will help rein in emergency room costs just as more than two million people are gaining coverage under the Affordable Care Act.  These findings also go against one of the central arguments of the law’s supporters, that extending insurance to large numbers of Americans would reduce emergency room use, and eventually save money.  This study could be surprising to many involved in the policy discussion.

It is important to note that many economists say that the emphasis on emergency room use is misplaced, as it makes up only a small part of health care costs in the United States. A federal government health survey found that emergency departments accounted for about 4 percent of total health spending in 2010, far less than inpatient hospital visits, which accounted for about 31 percent.