Opioid Use Disorder (OUD) is a chronic condition for which Medications for Opioid Use Disorder (MOUD) are crucial. Methadone Maintenance Treatment (MMT) and buprenorphine/naloxone (BN) are MOUD used to decrease opioid cravings and use, however, retention rates for MMT and BN vary. Genetic factors associated with retention in patients with other MOUD are largely unknown. The objective was to investigate the role of the T allele in rs204076 (found within Opioid Receptor Delta 1 gene) as a predictor for treatment retention in MOUD. Data were collected for the Pharmacogenetics of Opioid Substitution Treatment Response (POST) project. Retention time was calculated from the reported time of initiation of MOUD until loss to follow up or completion 12 month follow up using Kaplan-Meier survival analyses. A Cox regression analysis was conducted based on predictor variables for MOUD treatment retention. Of patients on MOUD(n = 1,607), majority were male (57%) and with an average age of 40 years. Survival time did not differ among carriers of the rs204076 T allele (p = 0.24). When controlling for non-genetic factors, individuals with the T allele had a 40% lower hazard of leaving treatment (Hazard Ratio HR = 0.60, 95% Confidence Interval CI = 0.44, 0.84, p = 0.002). MMT was associated with a 56% lower hazard of leaving treatment compared to BN (HR = 0.44, CI = 0.34, 0.58, p = 1.07 × 10− 9), however the benefit of MMT compared to BN was reduced in T allele carriers (HR = 1.43, 95% CI = 1.02, 2.00, p = 0.038) when controlling for non-genetic predictors of treatment retention. There was no association between sex and treatment retention. Understanding predictors of treatment retention including genetic variants in the OUD contributes to treatment personalized medicine and making informed treatment decisions regarding MOUD.
McEvoy et al. (Thu,) studied this question.