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Importance: Previous studies on the comparative effectiveness between buprenorphine and methadone provided limited evidence on differences in treatment effects across key subgroups and were drawn from populations who use primarily heroin or prescription opioids, although fentanyl use is increasing across North America., Objective: To assess the risk of treatment discontinuation and mortality among individuals receiving buprenorphine/naloxone vs methadone for the treatment of opioid use disorder., Design, Setting, and Participants: Population-based retrospective cohort study using linked health administrative databases in British Columbia, Canada. The study included treatment recipients between January 1, 2010, and March 17, 2020, who were 18 years or older and not incarcerated, pregnant, or receiving palliative cancer care at initiation., Exposures: Receipt of buprenorphine/naloxone or methadone among incident (first-time) users and prevalent new users (including first and subsequent treatment attempts)., Main Outcomes and Measures: Hazard ratios (HRs) with 95% compatibility (confidence) intervals were estimated for treatment discontinuation (lasting ≥5 days for methadone and ≥6 days for buprenorphine/naloxone) and all-cause mortality within 24 months using discrete-time survival models for comparisons of medications as assigned at initiation regardless of treatment adherence ("initiator") and received according to dosing guidelines (approximating per-protocol analysis)., Results: A total of 30 891 incident users (39% receiving buprenorphine/naloxone; 66% male; median age, 33 [25th-75th, 26-43] years) were included in the initiator analysis and 25 614 in the per-protocol analysis. Incident users of buprenorphine/naloxone had a higher risk of treatment discontinuation compared with methadone in initiator analyses (88.8% vs 81.5% discontinued at 24 months; adjusted HR, 1.58 [95% CI, 1.53-1.63]), with limited change in estimates when evaluated at optimal dose in per-protocol analysis (42.1% vs 30.7%; adjusted HR, 1.67 [95% CI, 1.58-1.76]). Per-protocol analyses of mortality while receiving treatment exhibited ambiguous results among incident users (0.08% vs 0.13% mortality at 24 months; adjusted HR, 0.57 [95% CI, 0.24-1.35]) and among prevalent users (0.08% vs 0.09%; adjusted HR, 0.97 [95% CI, 0.54-1.73]). Results were consistent after the introduction of fentanyl and across patient subgroups and sensitivity analyses., Conclusions and Relevance: Receipt of methadone was associated with a lower risk of treatment discontinuation compared with buprenorphine/naloxone. The risk of mortality while receiving treatment was similar for buprenorphine/naloxone and methadone, although the CI estimate for the hazard ratio was wide.

Background and Aim: In British Columbia, Canada, clinical guidelines for the treatment of opioid use disorders (OUD) were updated in 2017, during a period in which the potency and composition of the illicit drug supply changed rapidly. We aimed to describe changes in opioid agonist treatment (OAT) prescribing practices at the population level in a setting in which fentanyl and its analogs have become the primary illicit opioid of use., Design, Setting and Participants: This was a population-based retrospective cohort study using three linked health administrative databases in British Columbia (BC), Canada. All individuals with at least one OAT dispensation in BC between 1 January 2014 and 31 August 2021 took part., Measurements: To assess changes in OAT prescribing practices over time, we calculated initiation doses, dose titration intervals, maintenance doses and take-home dosing intervals stratified by medication [methadone, buprenorphine-naloxone and slow-release oral morphine (SROM)] according to recommended guidelines., Findings: A total of 265 410 OAT episodes (57.5% on methadone, 34.5% on buprenorphine-naloxone and 8.0% on SROM) were initiated during the study period. Compared with the guideline recommendation, observed initiation doses were higher among all medications from 2014 (2017 for SROM) to 2021 (buprenorphine-naloxone: 14-29%; methadone: 53-66%; SROM: 26-55%). Titration intervals were shorter for all medications, consistent with guidelines for buprenorphine-naloxone (26-49%), but shorter than recommended for methadone or SROM (28-51% and 12-41%, respectively). Higher maintenance dosing was observed for methadone (68-78%) and SROM (3-21%). Take-home allowances extending beyond the recommended guideline length increased across medications (buprenorphine-naloxone: 18-35%; methadone: 50-64%; SROM: 34-39%). Changes in prescribing patterns were similar for first-time OAT initiators., Conclusion: In British Columbia, Canada, from 2014 to 2021, prescribers of opioid agonist treatment (OAT) appeared to initiate both new and experienced OAT clients at higher doses than guideline recommendations, titrate them more rapidly and maintain clients at higher doses. Take-home dose allowances also gradually increased., (© 2024 The Authors. Addiction published by John Wiley & Sons Ltd on behalf of Society for the Study of Addiction.)

Introduction: Although randomized controlled trials (RCTs) examine "objective" indicators of safety and efficacy of investigational drugs, participants may not perceive study medications as neutral entities. Some medications are imbued with social and cultural meaning, such as stigmatized medications for opioid use disorders. Such perceptions surrounding substance use treatments can extend to the research context and shape RCT participants' experiences with and adherence to study medications., Methods: Considering these complexities in substance use research, we conducted a nested qualitative study within a multi-site, pragmatic RCT in Canada testing two treatments (methadone versus buprenorphine/naloxone) for opioid use disorder. Between 2017 and 2020, we conducted 115 interviews with 75 RCT participants across five trial sites in British Columbia, Alberta, Ontario, and Quebec., Results: Using an abductive coding approach, we characterized participants by their previous experience with medication for opioid use disorder and by their exposure to drug culture and drug scenes. Across these experience types, we identified systematic differences around participants' perceptions of the study medications, sources of information and expertise, and medication stigma., Conclusion: Our findings illustrate the critical importance of social context in shaping medication beliefs and study experiences among people who use drugs, with implications for the conduct of future RCTs in substance use., Competing Interests: Declaration of competing interest The authors have no conflicts of interest to declare., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Objective: Despite increased public awareness and use of opioid agonist therapy (OAT), there is little published data on contraception among women on methadone or buprenorphine/naloxone. This study aimed to characterize patterns of contraception use among this population., Methods: We conducted a cross-sectional survey between May 2014 and October 2015 at 6 medical clinics, pharmacies, and community organizations in British Columbia. Trained surveyors used the Canadian Sexual Health Survey (CSHS) to collect information on contraceptive practices and barriers to health care access. Descriptive analysis was performed on the subset of women on OAT who were at risk for unintended pregnancy., Results: Of the 133 survey respondents, 80 (60.2%) were at risk for unintended pregnancy. Among the 46 respondents with a recent pregnancy, 44 (95.7%) reported it as unintended. Of those at risk for unintended pregnancy, the most common contraceptive methods used were "no method," male condom, and depo-medroxyprogesterone at 28.8%, 16.3%, and 12.5%, respectively. Only 5% reported dual protection with a barrier and hormonal or intrauterine method. Barriers to contraception access included difficulty booking appointments with providers and cost, although 97% of all respondents reported feeling comfortable speaking with a physician about contraception., Conclusion: We found that most respondents using OAT reported prior pregnancies that were unintended, and used less effective contraceptive methods. Health care professionals who provide addiction care are uniquely positioned to address their patients' concerns about contraception. Incorporating family planning discussions into OAT services may improve understanding and use of effective contraceptive methods. Addressing unmet contraceptive needs may enable women on OAT to achieve their reproductive goals., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)

Introduction: Despite a recent meta-analysis including 31 randomised controlled trials comparing methadone and buprenorphine for the treatment of opioid use disorder, important knowledge gaps remain regarding the long-term effectiveness of different treatment modalities across individuals, including rigorously collected data on retention rates and other treatment outcomes. Evidence from real-world data represents a valuable opportunity to improve personalised treatment and patient-centred guidelines for vulnerable populations and inform strategies to reduce opioid-related mortality. Our objective is to determine the comparative effectiveness of methadone versus buprenorphine/naloxone, both overall and within key populations, in a setting where both medications are simultaneously available in office-based practices and specialised clinics., Methods and Analysis: We propose a retrospective cohort study of all adults living in British Columbia receiving opioid agonist treatment (OAT) with methadone or buprenorphine/naloxone between 1 January 2008 and 30 September 2018. The study will draw on seven linked population-level administrative databases. The primary outcomes include retention in OAT and all-cause mortality. We will determine the effectiveness of buprenorphine/naloxone vs methadone using intention-to-treat and per-protocol analyses-the former emulating flexible-dose trials and the latter focusing on the comparison of the two medication regimens offered at the optimal dose. Sensitivity analyses will be used to assess the robustness of results to heterogeneity in the patient population and threats to internal validity., Ethics and Dissemination: The protocol, cohort creation and analysis plan have been approved and classified as a quality improvement initiative exempt from ethical review (Providence Health Care Research Institute and the Simon Fraser University Office of Research Ethics). Dissemination is planned via conferences and publications, and through direct engagement and collaboration with entities that issue clinical guidelines, such as professional medical societies and public health organisations., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Studies assessing the comparative effectiveness of methadone versus buprenorphine/naloxone for opioid use disorder in real-world settings are rare - challenged by structural differences in delivery across settings and factors influencing treatment selection. We identified determinants of selection into buprenorphine/naloxone and quantified contributions of individual and provider-level covariates in a setting delivering both medications within the same healthcare settings., Methods: Utilizing linked health administrative datasets, we conducted a retrospective cohort study of people with opioid use disorder (PWOUD) receiving opioid agonist treatment (OAT) in British Columbia, Canada, from 2008-2017. Determinants of buprenorphine/naloxone selection were identified using a generalized linear mixed model with random intercept terms for providers and individuals. We determined the influence of individual demographics, clinical history, measures of provider experience and preference, and dates of key policy changes., Results: A total of 39,605 individuals experienced 178,976 OAT episodes (methadone:139,439(77.9 %);buprenorphine/naloxone:39,537(22.1 %)). Male sex, less OAT experience, younger age, mental health conditions and chronic pain were associated with higher odds of buprenorphine/naloxone prescription. For providers, higher client-attachment, more complex OAT case-mixes, and higher buprenorphine/naloxone prescribing-preference were also associated with higher odds of buprenorphine/naloxone prescription. Observed individual-level covariates explained 9.7 % of variance in odds of buprenorphine/naloxone selection, while observed provider-level covariates explained 20.0 %. Controlling for covariates, residual unmeasured between-individual variance accounted for 18.5 % of the explained variation in the odds of buprenorphine/naloxone selection, while unmeasured between-provider variance accounted for 28.4 %., Conclusion: Provider characteristics were more influential in selection of buprenorphine/naloxone over methadone informing subsequent analyses of comparative effectiveness of these regimens., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Objectives: Opioid agonist therapy is the cornerstone of treatment of opioid use disorder. In Canada, buprenorphine/naloxone has recently been adopted as the first line agonist therapy given its comparable effectiveness to methadone and superior safety profile. This study examines factors associated with willingness to take buprenorphine/naloxone among opioid users., Methods: Data were derived from two prospective cohorts of high-risk individuals who use drugs in Vancouver, Canada. Multivariable logistic regression analyses were used to determine factors associated with willingness to use buprenorphine/naloxone among people who use opioids and were not currently accessing this treatment option. Participants who were unwilling to use buprenorphine/naloxone were invited to provide reason(s) and their responses were examined in a sub-analysis., Results: Between December 2014 and May 2018, 1103 participants were interviewed. Overall, 194 (17.6%) respondents indicated that they would be willing to take buprenorphine/naloxone. Variables independently associated with willingness were previous buprenorphine/naloxone treatment (adjusted odds ratio [AOR] = 2.04), having ever used methadone treatment (AOR = 1.87), and age (AOR = 0.98, per year older) (all p < 0.05). Satisfaction with current agonist therapy (25.4%), not knowing what buprenorphine/naloxone is (25.1%), and wanting more information about buprenorphine/naloxone (15.1%) were the most commonly cited reasons for unwillingness. A low rate of willingness to use buprenorphine/naloxone (15.1%) was also observed among the sub-set of participants not using methadone., Conclusions: While an overall low level of willingness to take buprenorphine/naloxone was observed, this appeared to be largely driven by satisfaction with other agonists and a low prevalence of community knowledge about buprenorphine/naloxone., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Background and Aims: Cannabis use is common among people on opioid agonist treatment (OAT), causing concern for some care providers. However, there is limited and conflicting evidence on the impact of cannabis use on OAT outcomes. Given the critical role of retention in OAT in reducing opioid-related morbidity and mortality, we aimed to estimate the association of at least daily cannabis use on the likelihood of retention in treatment among people initiating OAT. As a secondary aim we tested the impacts of less frequent cannabis use., Design: Data were drawn from two community-recruited prospective cohorts of people who use illicit drugs (PWUD). Participants were followed for a median of 81 months (interquartile range = 37-130)., Setting: Vancouver, Canada., Participants: This study comprised a total of 820 PWUD (57.8% men, 59.4% of Caucasian ethnicity, 32.2% HIV-positive) initiating OAT between December 1996 and May 2016. The proportion of women was higher among HIV-negative participants, with no other significant differences., Measurements: The primary outcome was retention in OAT, defined as remaining in OAT (methadone or buprenorphine/naloxone-based) for two consecutive 6-month follow-up periods. The primary explanatory variable was cannabis use (at least daily versus less than daily) during the same 6-month period. Confounders assessed included: socio-demographic characteristics, substance use patterns and social-structural exposures., Findings: In adjusted analysis, at least daily cannabis use was positively associated with retention in OAT [adjusted odds ratio (aOR) = 1.21, 95% confidence interval (CI) = 1.04-1.41]. Our secondary analysis showed that compared with non-cannabis users, at least daily users had increased odds of retention in OAT (aOR = 1.20, 95% CI = 1.02-1.43), but not less than daily users (aOR = 1.00, 95% CI = 0.87-1.14)., Conclusions: Among people who use illicit drugs initiating opioid agonist treatment in Vancouver, at least daily cannabis use was associated with approximately 21% greater odds of retention in treatment compared with less than daily consumption., (© 2018 Society for the Study of Addiction.)