State Medicaid Policies Governing Access to Medications for Opioid Use Disorder (MOUD) and MOUD Treatment Use in a Large Sample of People Who Inject Drugs in 20 U.S. States.

Background: People who inject drugs (PWID) are especially vulnerable to harms from opioid use disorder (OUD). Medications for OUD (MOUD) effectively reduce overdose and infectious disease transmission risks.

Objective: We investigate whether state Medicaid coverage for methadone and buprenorphine is related to past-year MOUD use among PWID using cross-sectional, multilevel analyses with individual-level data on PWID from the Centers for Disease Control and Prevention's 2018 National HIV Behavioral Surveillance. The sample included 8,142 PWID aged 18-64 who reported daily opioid use from 22 U.S. metropolitan areas. Our outcome was any self-reported MOUD use in the past 12 months. Exposures were state Medicaid coverage and prior authorization requirements for methadone and buprenorphine. We interacted these exposures with PWID race/ethnicity, insurance status, and spatial access to treatment and harm reduction resources.

Results: Compared with PWID in states without Medicaid methadone coverage, odds of past-year MOUD use were 73% (<0.05) higher among PWID in states with methadone coverage requiring prior authorization and 80% (<0.05) higher among PWID in states with coverage without prior authorization. Insured PWID were twice as likely to report MOUD use than uninsured PWID, with no statistically significant differences between Medicaid versus other insurance. Medicaid prior authorization requirements for buprenorphine were not significantly associated with MOUD use. Non-Hispanic Black PWID were significantly less likely to use MOUD than non-Hispanic White and Hispanic PWID.

Conclusions: State Medicaid methadone coverage was strongly associated with higher odds that PWID utilized MOUD, suggesting that expanding methadone insurance coverage could improve MOUD treatment in a vulnerable population.