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Individuals with opioid use disorder (OUD) who received methadone were at lower risk for treatment discontinuation compared with buprenorphine and naloxone, according to findings published in JAMA.
International guidelines conflict about the best method of opioid agonist treatment (OAT) for OUD. In the current study, researchers compared outcomes from methadone and buprenorphine/naloxone using data from health administrative databases in British Columbia.
The researchers conducted a population-based retrospective cohort study and included all British Columbia OAT recipients between January 1, 2010, and March 17, 2020. The study population was defined using Drug Identification Numbers specific to OAT medications. The primary treatment variable was the form of OAT assigned at initiation, and the primary outcomes were OAT discontinuation and all-cause mortality during treatment.
In total, 30,891 patients who received OAT for OUD between 2010 and 2020 were evaluated for treatment discontinuation and mortality within 24 months. There were 18,891 patients assigned methadone and 11,910 patients assigned Buprenorphine/naloxone. The median (IQR) age of these two samples were 33 (26-43) and 33(25-44); 66.4% and 64.7% were men; 46.4% and 50.8% had received opioids before their first OUD indication; 63.8% and 65.8% had another substance use disorder; 23.7% and 24.4% had alcohol use disorder; and 87.6% and 88.2% had unstable housing, respectively.
Individuals without a history of OAT who initiated methadone sustained OAT treatment for a median of 66 (9-371) days compared with 30 (7-127) days with buprenorphine/naloxone. Incident buprenorphine/naloxone compared with methadone was associated with higher risk for treatment discontinuation (88.8% vs 81.5% discontinued at 24 months; adjusted hazard ratio [HR], 1.58; 95% CI, 1.53-1.63).
Among individuals with a history of OAT, a new initiation of buprenorphine/naloxone associated with increased risk for treatment discontinuation compared with methadone (HR, 1.44; 95% CI, 1.41-1.47).
Results of sensitivity analyses were largely consistent with the main analysis, even among youth and young adults, patients with comorbid pain, patients with severe mental disorders, and stratified by regional fentanyl concentration.
Mortality rates with buprenorphine/naloxone (range, 0.08%) and methadone (range, 0.09%-0.13%) were low. No significant differences in mortality risk were observed on the basis of OAT among incident (HR, 0.57; 95% CI, 0.24-1.35) and prevalent (HR, 0.97; 95% CI, 0.54-1.73) users.
The cumulative incidence curves suggested that mortality risk was not proportional over time between OATs, in which mortality risk initially tended to be lower with buprenorphine/naloxone (risk difference [RD], -0.1%; 95% CI, -0.4% to 0.1%). However, after 3 months this risk tended to be higher (RD, 1.3%; 95% CI, -0.3% to 3.6%) relative to methadone.
Among only incident users, high-dose buprenorphine/naloxone at 24/6 mg per day associated with lower mortality risk than methadone (HR, 0.08; 95% CI, 0.01-0.47).
Study authors concluded, “Clinical guidelines for all aspects of the treatment for people with opioid use disorders require reconsideration to reduce the risk of discontinuation treatment.”
This study was limited by the low mortality event rates, which may have led to imprecise outcomes.
Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.
This article originally appeared on Psychiatry Advisor
