Abstract
Objective: Early prognostic indicators of nonresponse to buprenorphine treatment for opioid use disorder can inform targeted efforts to improve outcomes. Opioid use in the first 2-3 weeks of treatment predicts later outcomes, yet it is unclear what frequency of opioid use confers risk. We aimed to (1) identify thresholds for the frequency of early opioid use that optimally predict later sustained use and (2) quantify associations between thresholds and continuous treatment outcomes. Method: We used data from 2 clinical trials of buprenorphine (N=562; mean age=34 years; 38% female), which were conducted from 2006-2009 and 2007-2011. Area under the receiver operating characteristic curve analyses identified optimal thresholds for opioid frequency during the first 4 weeks in predicting sustained use during weeks 5-12 (ie, 4 consecutive weeks with an opioid-positive or missing urine drug screen). Negative binomial regressions examined associations between early nonresponse and opioid-free and retention weeks. Results: Sustained opioid use was optimally predicted by ≥1 day of opioid use in the first 2 weeks (sensitivity=0.747; specificity=0.688; positive predictive value [PPV]=0.524; negative predictive value [NPV]=0.856) and ≥2 days of use in the first 3 weeks (sensitivity=0.649; specificity=0.810; PPV=0.611; NPV=0.834). Both thresholds were negatively associated with opioid-free and retention weeks. Conclusions: Even very low levels of opioid use in the first 2-3 weeks of buprenorphine treatment signal risk for poor outcomes. Emphasizing abstinence or near abstinence early in treatment might help promote long-term stability. Identified thresholds can be used to identify patients who may benefit from treatment adjustments and close monitoring.