The relationship between opioid agonist therapy satisfaction and fentanyl exposure in a Canadian setting.

BACKGROUND While patient-reported treatment dissatisfaction is considered an important factor in determining the success of substance use disorder treatment, the levels of dissatisfaction with opioid agonist therapies (OAT) and its relationship with the risk of fentanyl exposure have not been characterized in the context of the ongoing opioid overdose crisis in the US and Canada. Our primary hypothesis was that OAT dissatisfaction was associated with an increased odds of fentanyl exposure. METHODS Our objective was to examine self-reported treatment satisfaction among OAT patients in Vancouver, Canada and the association with fentanyl exposure. Longitudinal data were derived from 804 participants on OAT enrolled in two community-recruited harmonized prospective cohort studies of people who use drugs in Vancouver between 2016 and 2018 via semi-annual interviews and urine drug screens (UDS). We employed multivariable generalized estimating equations to examine the relationship between OAT dissatisfaction and fentanyl exposure. RESULTS Out of 804 participants (57.0% male), 222 (27.6%) reported being dissatisfied with OAT at baseline and 1070 out of 1930 observations (55.4%) had fentanyl exposure. The distribution of OAT reported in the sample was methadone (n = 692, 77.7%), buprenorphine-naloxone (n = 82, 9.2%), injectable OAT (i.e., diacetylmorphine or hydromorphone; (n = 65, 7.3%), slow-release oral morphine (n = 44, 4.9%) and other/study medication (n = 8, 1.0%). In the multivariable analysis, OAT dissatisfaction was positively associated with fentanyl exposure (AOR = 1.34; 95% CI: 1.08-1.66). CONCLUSIONS A substantial proportion of OAT patients in our sample reported dissatisfaction with their OAT, and more than half were exposed to fentanyl. We also found that those who were dissatisfied with their OAT were more likely to be exposed to fentanyl. These findings demonstrate the importance of optimizing OAT satisfaction in the context of the ongoing opioid overdose crisis.