The influence of poly-drug use patterns on the association between opioid agonist treatment engagement and injecting initiation assistance.
Stephanie A Meyers-Pantele, Maria Luisa Mittal, Sonia Jain, Shelly Sun, Indhu Rammohan, Nadia Fairbairn, M-J Milloy, Kora DeBeck, Kanna Hayashi, Dan Werb
Author Information
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.
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.
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.
M-J Milloy: British Columbia Centre on Substance Use, Vancouver, BC, Canada.
Kora DeBeck: British Columbia Centre on Substance Use, Vancouver, BC, Canada.
Kanna Hayashi: British Columbia Centre on Substance Use, 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. dwerb@health.ucsd.edu.
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 methamphetamineIDU and low-to-moderate-frequency prescription opioidIDU 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.
