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Bouck Z, Tricco AC, Rosella LC, Banack HR, Fox MP, Platt RW, Milloy MJ, DeBeck K, Hayashi K, Werb D. First-line opioid agonist treatment as prevention against assisting others in initiating injection drug use: A longitudinal cohort study of people who inject drugs in Vancouver, Canada. DRUG AND ALCOHOL DEPENDENCE REPORTS 2023; 7:100168. [PMID: 37397436 PMCID: PMC10311194 DOI: 10.1016/j.dadr.2023.100168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 05/18/2023] [Accepted: 05/19/2023] [Indexed: 07/04/2023]
Abstract
Background Among people who inject drugs, frequent injecting and experiencing withdrawal are associated with facilitating others' first injections. As these factors may reflect an underlying substance use disorder, we investigated whether first-line oral opioid agonist treatment (OAT; methadone or buprenorphine/naloxone) reduces the likelihood that people who inject drugs help others initiate injecting. Methods We used questionnaire data from semi-annual visits between December 2014-May 2018 on 334 people who inject drugs with frequent non-medical opioid use in Vancouver, Canada. We estimated the effect of current first-line OAT on subsequent injection initiation assistance provision (i.e., helped someone initiate injecting in the following six months) using inverse-probability-weighted estimation of repeated measures marginal structural models to reduce confounding and informative censoring by time-fixed and time-varying covariates. Results By follow-up visit, 54-64% of participants reported current first-line OAT whereas 3.4-6.9% provided subsequent injection initiation assistance. Per the primary weighted estimate (n = 1114 person-visits), participants currently on first-line OAT (versus no OAT) were 50% less likely, on average, to subsequently help someone initiate injecting (relative risk [RR]=0.50, 95% CI=0.23-1.11). First-line OAT was associated with reduced risk of subsequent injection initiation assistance provision in participants who, at baseline, injected opioids less than daily (RR=0.15, 95% CI=0.05-0.44) but not in those who injected opioids daily (RR=0.86, 95% CI=0.35-2.11). Conclusions First-line OAT seemingly reduces the short-term likelihood that people who inject drugs facilitate first injections. However, the extent of this potential effect remains uncertain due to imprecise estimation and observed heterogeneity by baseline opioid injecting frequency.
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Affiliation(s)
- Zachary Bouck
- Epidemiology Division, Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada
- Centre on Drug Policy Evaluation, St. Michael's Hospital, Unity Health Toronto, Toronto, ON, Canada
| | - Andrea C. Tricco
- Epidemiology Division, Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada
- Knowledge Translation Program, St. Michael's Hospital, Unity Health Toronto, Toronto, ON, Canada
- Institute for Health Policy, Management and Evaluation, University of Toronto, Toronto, ON, Canada
| | - Laura C. Rosella
- Epidemiology Division, Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada
- ICES, Toronto, ON, Canada
| | - Hailey R. Banack
- Epidemiology Division, Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada
| | - Matthew P. Fox
- Department of Epidemiology, Boston University School of Public Health, Boston, MA, United States
- Department of Global Health, Boston University School of Public Health, Boston, MA, United States
| | - Robert W. Platt
- Department of Epidemiology, Biostatistics, and Occupational Health, McGill University, Montréal, QC, Canada
- Department of Pediatrics, McGill University, Montréal, QC, Canada
| | - M-J Milloy
- British Columbia Centre for Substance Use, Vancouver, BC, Canada
- Department of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Kora DeBeck
- British Columbia Centre for Substance Use, Vancouver, BC, Canada
| | - Kanna Hayashi
- British Columbia Centre for Substance Use, Vancouver, BC, Canada
- Faculty of Health Sciences, Simon Fraser University, Burnaby, BC, Canada
| | - Dan Werb
- Centre on Drug Policy Evaluation, St. Michael's Hospital, Unity Health Toronto, Toronto, ON, Canada
- Institute for Health Policy, Management and Evaluation, University of Toronto, Toronto, ON, Canada
- Division of Infectious Diseases and Global Public Health, University of California San Diego, La Jolla, CA, United States
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Meyers-Pantele SA, Mittal ML, Jain S, Sun S, Rammohan I, Fairbairn N, Milloy MJ, DeBeck K, Hayashi K, Werb D. The influence of poly-drug use patterns on the association between opioid agonist treatment engagement and injecting initiation assistance. Subst Abuse Treat Prev Policy 2022; 17:39. [PMID: 35590419 PMCID: PMC9118611 DOI: 10.1186/s13011-022-00470-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/06/2022] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND Evidence suggests people who inject drugs (PWID) prescribed opioid agonist treatment (OAT) are less likely to provide injection drug use (IDU) initiation assistance. We investigated the association between OAT engagement and providing IDU initiation assistance across poly-drug use practices in Vancouver, Canada. METHODS Preventing Injecting by Modifying Existing Responses (PRIMER) is a prospective study seeking to identify structural interventions that reduce IDU initiation. We employed data from linked cohorts of PWID in Vancouver and extended the findings of a latent profile analysis (LPA). Multivariable logistic regression models were performed separately for the six poly-drug use LPA classes. The outcome was recently assisting others in IDU initiation; the independent variable was recent OAT engagement. RESULTS Among participants (n = 1218), 85 (7.0%) reported recently providing injection initiation assistance. When adjusting for age and sex, OAT engagement among those who reported a combination of high-frequency heroin and methamphetamine IDU and low-to-moderate-frequency prescription opioid IDU and methamphetamine non-injection drug use (NIDU) was associated with lower odds of IDU initiation assistance provision (Adjusted Odds Ratio [AOR]: 0.18, 95% CI: 0.05-0.63, P = 0.008). Significant associations were not detected among other LPA classes. CONCLUSIONS Our findings extend evidence suggesting that OAT may provide a population-level protective effect on the incidence of IDU initiation and suggest that this effect may be specific among PWID who engage in high-frequency methamphetamine and opioid use. Future research should seek to longitudinally investigate potential causal pathways explaining the association between OAT and initiation assistance provision among PWID to develop tailored intervention efforts.
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Affiliation(s)
- Stephanie A Meyers-Pantele
- Division of Infectious Diseases and Global Public Health, Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0507, USA
- Department of Psychology, San Diego State University, San Diego, CA, USA
| | - Maria Luisa Mittal
- Division of Infectious Diseases and Global Public Health, Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0507, USA
- School of Medicine, Universidad Xochicalco, Tijuana, BC, Mexico
| | - Sonia Jain
- Department of Family Medicine and Public Health, University of California San Diego, La Jolla, CA, USA
| | - Shelly Sun
- Department of Family Medicine and Public Health, University of California San Diego, La Jolla, CA, USA
| | - Indhu Rammohan
- Centre on Drug Policy Evaluation, St. Michael's Hospital, 30 Bond Street, Toronto, ON, M5B 1W8, Canada
| | - Nadia Fairbairn
- British Columbia Centre on Substance Use, Vancouver, BC, Canada
- Department of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - M-J Milloy
- British Columbia Centre on Substance Use, Vancouver, BC, Canada
- Department of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Kora DeBeck
- British Columbia Centre on Substance Use, Vancouver, BC, Canada
- School of Public Policy, Simon Fraser University, Vancouver, BC, Canada
| | - Kanna Hayashi
- British Columbia Centre on Substance Use, Vancouver, BC, Canada
- Faculty of Health Sciences, Simon Fraser University, Vancouver, BC, Canada
| | - Dan Werb
- Division of Infectious Diseases and Global Public Health, Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0507, USA.
- Centre on Drug Policy Evaluation, St. Michael's Hospital, 30 Bond Street, Toronto, ON, M5B 1W8, Canada.
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Evaluating interventions to facilitate opioid agonist treatment access among people who inject drugs in Toronto, Ontario during COVID-19 pandemic restrictions. THE INTERNATIONAL JOURNAL OF DRUG POLICY 2022; 104:103680. [PMID: 35447476 PMCID: PMC9005368 DOI: 10.1016/j.drugpo.2022.103680] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 03/22/2022] [Accepted: 03/30/2022] [Indexed: 12/01/2022]
Abstract
Background In March 2020, following a provincial COVID-19 emergency declaration, modifications to opioid agonist treatment (OAT) were introduced in Ontario, Canada to promote treatment access amid the pandemic and ongoing opioid overdose crisis. Modifications included federal exemptions to facilitate OAT prescription re-fills, extensions, and deliveries and interim treatment guidance emphasizing take-home (non-observed) doses and reduced urine drug screening for OAT patients. Methods We conducted an interrupted time series study using health administrative data from September 17th, 2019–September 21st, 2020, on 359 people who inject drugs with suspected opioid use disorder in Toronto, Ontario. We used segmented regression analyses to evaluate the joint effects of the provincial COVID-19 emergency declaration, federal OAT exemptions, and interim treatment guidance—all implemented between March 17th–23rd, 2020—on the weekly proportion of participants enrolled in OAT (i.e., ≥1 day(s) covered with methadone or buprenorphine/naloxone), with an opioid-related overdose (based on emergency department visits and hospitalizations), and who died (all-cause), and the weekly proportion of OAT-enrolled participants receiving take-home doses (i.e., ≥1 day(s) covered) and undergoing urine drug screening. Results Post-implementation, the interventions were associated with immediate absolute changes in OAT enrollment (+1.95%; 95% CI=0.04%–3.85%), receipt of take-home doses (+18.3%; 95% CI=13.2%–23.4%), and urine drug screening (-22.4%; 95% CI=[-26.9%]–[-17.9%]) and a gradual absolute increase of 0.56% in urine drug screening week-to-week (95% CI=0.27%–0.86%) beyond the pre-implementation trend. At 26 weeks post-implementation, OAT enrollment and urine drug screening approached pre-implementation levels whereas the increase in take-home doses was largely sustained (+15.0%; 95% CI=4.33%–25.6%). No post-implementation increases in opioid-related overdoses were observed. Death was not modelled (low event frequency). Conclusion Changes to OAT provision following provincial COVID-19 restrictions were associated with an immediate and sustained increase in take-home dose coverage among OAT-enrolled participants, without corresponding increases in opioid-related overdoses among all participants.
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