Patients with OUD less likely to stop methadone than buprenorphine/naloxone
Results were consistent after fentanyl became present in the population and across a range of subgroup and sensitivity analyses.
Methadone was associated with a lower risk of treatment discontinuation for opioid use disorder (OUD) compared with buprenorphine/naloxone, a study found.
To assess the risk of stopping treatment and mortality among people receiving buprenorphine/naloxone or methadone for OUD, researchers conducted a population-based retrospective cohort study using linked health administrative databases in British Columbia, Canada, from January 2010 through March 2020. Patients initiating buprenorphine/naloxone or methadone who were not incarcerated, pregnant, or receiving palliative cancer care were included. Treatment discontinuation was defined as breaks in days dispensed lasting five days or more for methadone and six days or more for buprenorphine/naloxone. Researchers estimated treatment stoppage and all-cause mortality within 24 months using discrete-time survival models. Results were published by JAMA on Oct. 17.
Overall, 30,891 users were included in the initiator analysis and 25,614 in the per protocol analysis. Buprenorphine/naloxone was associated with a higher risk of stopping treatment compared with methadone in initiator analyses (88.8% vs. 81.5% at 24 months; adjusted hazard ratio [HR], 1.58 [95% CI, 1.53 to 1.63]). There was limited change when medications were evaluated at optimal dose in the per protocol analysis (42.1% vs. 30.7%; adjusted HR, 1.67 [95% CI, 1.58 to 1.76]). Results of per protocol analyses of mortality while receiving treatment were not significantly different among incident users (0.08% vs. 0.13% at 24 months; adjusted HR, 0.57 [95% CI, 0.24 to 1.35]) or prevalent users (0.08% vs. 0.09%; adjusted HR, 0.97 [95% CI, 0.54 to 1.73]).
The study authors wrote that sensitivity analyses supported the primary findings and favored methadone across initiator and per protocol analyses and within incident user and prevalent new-user cohorts. The results were also consistent when the analysis was restricted to the calendar period after initial detection of fentanyl in the provincial coroner's reports.
“These results add to a growing evidence base consistent with methadone offering greater effectiveness in promoting sustained retention for individuals receiving [opioid agonist treatment]; the findings fall within the range reported by a large systematic review,” the authors wrote. “These results were largely unchanged after fentanyl first appeared in the illicit drug supply, and results were consistent across patient subgroups.”
A separate viewpoint in the same issue of JAMA elaborated on past politics of drug treatment and the role of methadone in the future.
Methadone's role in improving health and reducing overdose deaths has been hindered by decades-old policies that limit its delivery to licensed opioid treatment programs, commonly called “methadone clinics,” that require daily observed dosing among other restrictions, the viewpoint said. But reforms are underway, it continued.
Recent advances in federal methadone treatment policy and the Modernizing Opioid Treatment Access Act, a bill in Congress, could “catalyze a sea change in OUD care delivery, matching the unprecedented health crisis that our nation faces,” the viewpoint said. However, states must remove policies even more restrictive than federal laws, and there must be investment in health care delivery systems, it noted.