Abstract
BACKGROUND: Opioid craving is suggested to correlate with the rate of reduction in buprenorphine (BUP) plasma levels. No studies explored Buprenorphine elimination rate constant (BUP EL.R) as a predictor of opioid use or retention in BUP treatment. METHODS: Analysis was performed using data from a randomized controlled trial of 141 adults with opioid use disorder (OUD) randomized to Incentivized Adherence and Abstinence monitoring (I-AAM; experimental (n = 70) and treatment-as-usual; control (n = 71). In the I-AAM, structured access to unsupervised BUP doses was provided up to 28 days contingent of adherence measured by Therapeutic Drug Monitoring and abstinence by Urinary Drug Screens (UDS). In contrast, the treatment-as-usual (control) provided unstructured access to unsupervised doses was provided for up to 14 days considering UDS results. The primary outcome was percentage negative UDS. The secondary outcome, retention in treatment, was continuous enrollment in the study and analysis was via intention-to-treat. Significant bivariate correlations with the outcomes were adjusted for group allocation. RESULTS: A significant negative correlation between BUP EL.R and percentage negative opioid screens (Pearson correlation coefficient - 0.57, p < 0.01) was found. After adjusting for trial group, BUP EL.R was shown to be an independent predictor of percentage negative opioid screens (Standardized Beta Coefficient - 0.57, 95% CI - 221.57 to - 97.44, R(2) 0.322). CONCLUSION: BUP EL.R predicted 32.2% of the variation in percentage negative opioid UDS and may serve as a potential promising tool in precision medicine of BUP treatment. Higher buprenorphine elimination is associated with higher positive opioid urine screens during treatment. TRIAL REGISTRATION: ISRCTN41645723 retrospectively registered on 15/11/2015.