Despite a national opioid overdose epidemic supercharged by a surge of illicit fentanyl, new research from Oregon Health & Science University reveals wide discrepancies among U.S. states in effectively treating opioid use disorder among people covered by Medicaid.

The study, published in the journal JAMA Health Forum, found that in many states, fewer than half of people diagnosed with opioid use disorder received proven medications to treat it.

"We fail people by not providing adequate treatment to people with opioid use disorder enrolled in Medicaid," said lead author Stephan Lindner, Ph.D., associate professor in the OHSU Center for Health Systems Effectiveness. Medicaid provides health care coverage to more than 90 million Americans.

Evidence strongly suggests that medication should be nearly universal treatment for people with opioid use disorder, said co-author Dennis McCarty, Ph.D., professor emeritus of public health in the OHSU School of Medicine and the OHSU-Portland State University School of Public Health.

The study documented wide variability in access to medication for opioid use disorder.

In some Northeast states, up to 75% of patients covered by Medicaid and diagnosed with opioid use disorder received buprenorphine, methadone or naltrexone. In contrast, among Medicaid recipients living in the Midwest and the South, fewer than 25% of individuals diagnosed with opioid use disorder received one of the three medications approved by the Food and Drug Administration for treatment. Oregon fell roughly in the middle, with a rate of 61%—slightly above the nationwide average of 55%.

In some counties, the rate was less than 10%.

"The variability suggests quality of care problems," McCarty said. "It reveals lost opportunities to intervene prior to fatal and nonfatal overdoses."

A record 109,000 people in the U.S. died of drug overdoses in 2022, according to provisional data released by the Centers for Disease Control and Prevention.

Researchers conducted the study using a newly available set of Medicaid claims data, examining claims among individuals enrolled in Medicaid between 2016 and 2018 at the state and county level. Researchers also noted that the study is limited by data quality across states, and the fact that Medicaid claims records only capture people with opioid use disorder who are in contact with health care professionals.