Congressional Republicans’ plan to repeal the Affordable Care Act and end Medicaid expansion would imperil efforts to fight the opioid crisis, according to a public health school study.

Legislation that would stop Medicaid expansion, a centerpiece of the GOP’s healthcare plans, could threaten the financial health of hospitals in states affected by the opioid crisis, putting addicts and other community members at risk if hospitals are forced to close, the study found.

Leighton Wu, the director of the Center for Health Policy Research, and Naomi Seiler, an associate research professor of Health Policy and Management, co-authored the study and analyzed emergency room and hospital admissions in four southern states hard hit by opioid addiction.

The study most closely looked at West Virginia and Kentucky, which expanded Medicaid, and North Carolina and Virginia who did not.

The study found that states that expanded Medicaid under the Affordable Care Act – known as Obamacare – were able to more efficiently deal with opioid-related hospital visits because Medicaid covered the cost of the surge in emergency room visits. In states that opted not expand Medicaid, hospitals were not compensated for providing live-saving care to addicts.

“Beyond covering the initial ER visit or hospital admission, Medicaid coverage can play a significant role helping people addicted to opioids get care needed, including rehabilitation, outside the hospital,” researchers said in a release.