Comparative effectiveness of take-home dosing schedules for opioid agonist treatment in British Columbia, Canada: a...

The introduction of fentanyl and its analogues in the illicit drug supply has prompted greater emphasis on refining clinical treatment protocols to ensure sustained retention in opioid agonist treatment (OAT). Take-home dosing may lessen the treatment burden on clients and thus reduce the risk of treatment discontinuation. The evidence base supporting the use of take-home dosing, including the optimal duration of dispensations, is, however, limited. The objective of this study is to determine the comparative effectiveness of alternative take-home dosing schedules, as observed in clinical practice in British Columbia, Canada from 2010 to 2022.

We propose to emulate a target trial with a population-level retrospective study of individuals initiating methadone or buprenorphine/naloxone between 1 January 2010 and 31 December 2022 who are 18 years of age or older and not currently incarcerated or pregnant with no history of cancer or palliative care. Our study will draw on nine linked health administrative databases from British Columbia and will evaluate take-home doses of 2-5 days, 6 days or >6 days compared with continuous daily dosing. The primary outcomes include OAT discontinuation and all-cause mortality on treatment. A causal per-protocol analysis is proposed with longitudinal matching and inverse probability of censoring weighting approaches to adjust for time-fixed and time-varying confounding. A range of sensitivity analyses will be executed to determine the robustness of results.

The protocol, cohort creation and analysis plan have been classified and approved as a quality improvement initiative by Providence Health Care Research Ethics Board and the Simon Fraser University Office of Research Ethics. Results will be disseminated and shared with local advocacy groups and decision-makers, developers of national and international clinical guidelines, presented at national and international conferences and published in peer-reviewed journals electronically and in print.