The impact of Medicaid expansion: More trips to the ER, but fewer patients are uninsured

Doctor and nurses wheeling patient in gurney through hospital corridor
Emergency room visits increased in states that expanded Medicaid coverage under the Affordable Care Act, but more of those patients had insurance, according to a new analysis. Getty/Sam Edwards

Emergency room visits increased in states that expanded Medicaid coverage under the Affordable Care Act, but more of those patients had insurance, according to a new analysis.

The study, published today in Annals of Emergency Medicine, found that after 2014, states that expanded Medicaid saw an 8.8% increase in the number of ER visits covered by Medicaid. But the share of those visits by the uninsured decreased by 5.3%.

Researchers analyzed patients in 25 states, including 14 states that expanded Medicaid and 11 that did not. The share of visits covered by private insurance remained the same for expansion states, but increased by several percentage points for nonexpansion states. Gains in insurance coverage in nonexpansion states were almost entirely in the form of private coverage, not Medicaid.

"Medicaid expansion had a larger impact on the healthcare system in places where more people were expected to gain coverage," lead study author Sayeh Nikpay, Ph.D., Department of Health Policy, Vanderbilt University School of Medicine, Nashville, Tennessee, said in a study announcement. "The change in total visits was twice as large in a state like Kentucky, where most childless adults were ineligible for Medicaid at any income level before 2014, as in states like Hawaii, where childless adults were already eligible for Medicaid above the poverty line."

RELATED: Medicaid expansion slashed uninsured rates for poor, childless adults

The most common type of visit to the ER was for injury-related visits. However, there was a large change in payer mix for dental visits, which researchers believe are because dental emergency visits are most prevalent among low-income, nonelderly adults who would be covered by Medicaid.

In an accompanying opinion piece, Ari Friedman, M.D., Ph.D., of Beth Israel Deaconess Medical Center in Boston, said the findings run contrary to what many policymakers believed would happen if the government expanded Medicaid: that ED volume would go down.

“More emergency department visits by Medicaid beneficiaries is neither clearly bad nor clearly goo,” he wrote. “Insurance increases access to care, including emergency department care. We need to move beyond the value judgments that have dominated so much study of emergency department utilization towards a more rational basis for how we structure unscheduled visits in the health system. If we want to meet patients' care needs as patients themselves define them, the emergency department has a key role to play in a flexible system.”