Study finds uninsured don't use emergency rooms more than other patients

One of the most common arguments for expanding publicly subsidized health coverage is that the uninsured overuse and overburden emergency departments. This argument persists despite evidence that, when the uninsured gain Medicaid coverage, emergency department use increases.

A new study by Katherine Baicker, dean and Emmett Dedmon professor at the University of Chicago Harris School of Public Policy, and co-authors sheds light on the potential sources of the disconnect between the evidence and the conventional wisdom.

The researchers' descriptive findings, published in the December issue of Health Affairs, confirm that those without insurance do not use emergency departments more than those with insurance, and actually use them much less than those on Medicaid. Furthermore, the uninsured and the insured use the emergency department for very similar kinds of care, dispelling the misperception that the uninsured are much more likely to go to the emergency department for less serious conditions.

"We found that working-age adults with or without insurance use emergency departments at very similar rates and under similar circumstances," said Baicker.

The researchers noted, however, that the uninsured are much less likely to use other kinds of care than the insured. "The uninsured don't use other types of care, such as outpatient clinics or hospitals, as much as the insured do," Baicker added. "This finding may contribute to the notion that the uninsured overuse emergency departments – other patients and providers are more likely to see the uninsured in emergency departments than in other settings."

Baicker and fellow researchers Amy Finkelstein of the Massachusetts Institute of Technology, Sarah Taubman, and Ruohua Annetta Zhou of Harvard, gathered their data for these conclusions from two national data sources: the Medical Expenditure Survey and the National Hospital Ambulatory Care Survey. These findings provide context for results from the Oregon Health Insurance Experiment, a randomized controlled evaluation of the impact of expanding Medicaid to cover working-age adults, which showed that expanding Medicaid coverage increased emergency department use.

The perception that the uninsured overuse emergency departments relative to the insured is pervasive in the debate about the future of public insurance programs like Medicaid. This research suggests that a focus on emergency department utilization alone is misguided.