A new analysis of more than 2600 patients with opioid use disorder found that while methadone improves treatment retention, buprenorphine may be more effective in reducing illicit opioid use among lower-risk patients.
Led by Leen Naji of The University of Arizona College of Medicine Phoenix and McMaster University, the researchers followed participants over 12 months across 54 treatment sites and compared methadone maintenance therapy (MMT) and buprenorphine-naloxone (bup/nal).
They found that 13.5% of patients on methadone were classified as nonresponders—defined as having more than half of their urine drug screens test positive for nonprescribed opioids—compared with 8.1% of those on buprenorphine. Although this difference was notable, statistical analysis showed it was not significant after adjusting for baseline factors such as age, sex, employment status, and substance use history.
Methadone was significantly associated with higher treatment retention. Patients on MMT were nearly twice as likely to remain in treatment at 12 months compared with those on bup/nal (odds ratio [OR] = 1.79, 95% confidence interval [CI] = 1.45–2.22). Additional predictors of retention included being female, older, employed, and no history of intravenous drug use (IVDU) or opioid overdose.
Among participants without a history of IVDU—considered a marker of lower-risk opioid use disorder (OUD)—those receiving MMT were more likely to continue using illicit opioids than those on bup/nal (OR = 1.72, 95% CI = 1.07–2.77). No significant difference was observed in treatment response among patients with a history of IVDU. Similar patterns were seen when outcomes were analyzed by overdose history.
The cohort included 2068 patients on MMT and 533 on bup/nal. The average age was 39 years, and 45% were women. Most participants underwent frequent urine drug screening, averaging nearly 50 screens over the 12-month period.
The study’s strengths included its large, representative sample, long follow-up period, and use of objective outcome measures. Minimal exclusion criteria allowed inclusion of patients with concurrent substance use or comorbid conditions which enhanced generalizability. However, as an observational study, it remained subject to potential unmeasured confounding despite propensity score matching.
Researchers noted that while methadone may support treatment retention, this metric alone may not "correlate with improvements in patient-centered outcomes." They suggested future research should prioritize patient-centered outcomes, such as quality of life, cravings, and functional status, and should employ pragmatic trial designs that are reflective of real-world care settings.
These findings provide relevant insights for clinicians making treatment decisions for OUD, particularly amid rising fentanyl use and increasing opioid overdose deaths.
Full disclosures can be found in the published study.
Source: BMJ Open
