The rising prevalence of prescription opioid injection and its association with hepatitis C incidence among street-drug users
Article first published online: 22 MAR 2012
© 2012 The Authors, Addiction © 2012 Society for the Study of Addiction
Volume 107, Issue 7, pages 1318–1327, July 2012
How to Cite
Bruneau, J., Roy, É., Arruda, N., Zang, G. and Jutras-Aswad, D. (2012), The rising prevalence of prescription opioid injection and its association with hepatitis C incidence among street-drug users. Addiction, 107: 1318–1327. doi: 10.1111/j.1360-0443.2012.03803.x
- Issue published online: 6 JUN 2012
- Article first published online: 22 MAR 2012
- Accepted manuscript online: 16 JAN 2012 03:01PM EST
- Submitted 17 August 2011; initial review completed 9 January 2012; final version accepted 10 January 2012
- Cohort study;
- HCV incidence;
- illicit opioid misuse;
- injection drug use;
- injection risk behaviour;
- prescription opioid
Aims To examine trends in prescription opioid (PO) injection and to assess its association with hepatitis C virus (HCV) seroconversion among injection drug users (IDUs).
Design Prospective cohort study.
Setting Montreal, Canada.
Participants HCV-negative IDUs at baseline, reporting injection in the past month.
Measurements Semi-annual visits included HCV antibody testing and an interview-administered questionnaire assessing risk behaviours. HCV incidence rate was calculated using the person–time method. Time-updated Cox regression models were conducted to examine predictors of HCV incidence.
Findings The proportion of IDUs reporting PO injection increased from 21% to 75% between 2004 and 2009 (P < 0.001). Of the 246 participants (81.6% male; mean age 34.5 years; mean follow-up time 23 months), 83 seroconverted to HCV [incidence rate: 17.9 per 100 person-years; 95% confidence interval (CI) 14.3, 22.1]. Compared to non-PO injectors, PO injectors were more likely to become infected [adjusted hazard ratio (AHR): 1.87; 95%CI:1.16, 3.03]. An effect modification was also found: PO injectors who did not inject heroin were more likely to become infected (AHR: 2.88; 95%CI: 1.52, 5.45) whereas no association was found for participants using both drugs (AHR: 1.19; 95% CI: 0.61, 2.30). Other independent predictors of HCV incidence were: cocaine injection, recent incarceration and >30 injections per month.
Conclusions Prescription opioid injectors who do not inject heroin are at greater risk for HCV seroconversion than are those injecting both heroin and prescription opioids. Important differences in age, behaviour and social context suggest a need for targeted outreach strategies to this population.