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Langlois, Jenna Marie

University of British Columbia

Background: North America is facing an opioid epidemic primarily attributable to potent synthetic opioids. There has been a marked increase in methamphetamine/amphetamine use and related harms among people who use opioids. However, little is known about this population and their treatment-related outcomes. The aim of this thesis was to characterize the population of people with prescription-type opioid use disorder (POUD) who use methamphetamine/amphetamine, and to determine the effects of methamphetamine/amphetamine use and opioid agonist therapy (OAT) on treatment-related outcomes. Methods: Secondary analysis of a pan-Canadian pragmatic trial comparing supervised methadone versus flexible take-home dosing buprenorphine/naloxone models of care among POUD. Multivariable logistic regression analyses were used to determine correlates of baseline methamphetamine/amphetamine use (measured by urine drug test [UDT] and self-report). Cox proportional hazard models were used to evaluate the impact of baseline methamphetamine/amphetamine use on OAT discontinuation. Generalized linear mixed models were used to examine the comparative effectiveness of buprenorphine/naloxone versus methadone on methamphetamine/amphetamine use. Results: Among the 272 randomized participants, 185 (68.0%) were using methamphetamine/amphetamine at baseline. Fentanyl use in the last 30 days (adjusted odds ratio [AOR] = 11.59, 95% confidence interval [CI] = 5.90 – 23.68] was independently and positively associated with baseline methamphetamine/amphetamine use. Among participants that initiated treatment (n = 210), 130 (61.9%) were using methamphetamine/amphetamine at baseline. Baseline methamphetamine/amphetamine use was associated with shorter median times in assigned OAT (36 versus 168 days, adjusted hazard ratio [aHR] = 2.07, CI = 1.22 – 3.49) and any OAT (41 days versus 168 days, aHR = 1.83, CI = 1.05 – 3.17). Neither treatment type nor time in treatment were significantly associated with the odds of methamphetamine/amphetamine use (p > 0.05). Conclusions: In this sample of people with POUD, methamphetamine/amphetamine use was associated with markers of complex and severe OUD, including fentanyl exposure, and increased risk of OAT discontinuation. Methadone and buprenorphine/naloxone did not have an impact on methamphetamine/amphetamine use over the 24-week intervention. These findings suggest the need for targeted interventions, including development of evidence-based treatments for methamphetamine/amphetamine use within specific subgroups, to prevent future overdoses and optimize treatment outcomes in this population.

Text

2024-04-02

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/87666

Experimental Medicine

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/