Prescription opioid use and non-fatal overdose in a cohort of injection drug users

Abstract

Background: There is growing concern regarding rising rates of prescription drug-related deaths among the general North American population as well as increasing availability of illicitly obtained prescription opioids. Concurrently among people who inject drugs (IDU), illicit prescription opioid use has increased while non-fatal overdose remains a major source of morbidity. Objectives: To evaluate whether the use of prescription opioids was associated with non-fatal overdose among IDU in Vancouver, Canada. Methods: Data was obtained from two open prospective cohorts of IDU between December 2005 and May 2013. We used generalized estimating equation (GEE) logistic regression to evaluate the association between prescription opioid use and non-fatal overdose, adjusting for various social, demographic, and behavioral factors. Results: There were 1614 IDU, including 541 (33.5%) women, who were recruited and included in this analysis. At baseline, 526 (32.6%) reported using prescription opioids and 118 (7.3%) reported experiencing an overdose in the previous six months. In a multivariable analysis, prescription opioid use remained independently associated with non-fatal overdose (adjusted odds ratio: 1.61, 95% confidence interval: 1.32–1.95), after adjusting for confounders. Conclusion: We observed relatively high rates of prescription opioid use among IDU in this setting, and found an independent association between prescription opioid use and non-fatal overdose. Our data is likely representative of riskier substance use associated with those who use prescription opioids within our sample. Interventions to prevent and respond to overdoses should consider the higher risk profiles of IDU who use prescription opioids.

• Injection drug use
• non-fatal overdose
• opioid analgesics
• prescription opioids

Acknowledgements

The authors thank the VIDUS and ACCESS participants for their contribution to the research, as well as current and past researchers and staff. We would also like to thank the staff of the British Columbia Centre for Excellence in HIV/AIDS for their administrative assistance.

Funding

This study is supported by the US National Institutes of Health (R01DA021525 and R01DA011591). Dr. Wood is funded by the Canada Research Chairs Program through a Tier 1 Canada Research Chair in Inner City Medicine.

Declaration of interest

Dr Montaner has received grants from, served as an ad hoc adviser to, or spoken at events sponsored by Abbott, Argos Thera- peutics, Bioject Inc., Boehringer Ingelheim, BMS, Gilead Sciences, GlaxoSmithKline, Hoffmann-La Roche, Janssen-Ortho, Merck Frosst, Panacos, Pfizer Ltd., Schering, Serono Inc., TheraTechnologies, Tibotec (J&J), and Trimeris. All the other authors report no conflicts of interest. The authors alone are responsible for the content and writing of this paper.