OBJECTIVES

To evaluate the prevalence and correlates of non-fatal overdose among a polysubstance-using cohort of injection drug users (IDU) in Vancouver.

STUDY DESIGN/METHODS: We evaluated factors associated with non-fatal overdose among participants enrolled in the Vancouver Injection Drug Users Study (VIDUS) using univariate statistics. Self-reports of the awareness of drugs taken and drug potency, polysubstance use, and assistance received at the time of non-fatal overdose were also recorded.

RESULTS

From 1 December 2003 to 1 June 2005, 551 participants who were active injectors were followed. In total, 37 (6.7%) individuals reported experiencing a non-fatal overdose in the previous 6 months. Factors positively associated with non-fatal overdose included public injecting (odds ratio (OR)=4.74, 95% confidence interval (CI) 2.35-9.37, P<0.001), crystal methamphetamine use (OR=4.11) and injection (OR=3.63), morphine injection (OR=3.55), non-injection opiate use (OR=3.30), frequent heroin injection (OR=2.28) and sex trade work (OR=2.12). Factors negatively associated with non-fatal overdose included participation in methadone maintenance therapy (OR=0.31) and injecting alone (OR=0.36). Sixty-two percent of individuals were unaware of drug potency, 64.9% of IDU were taking other drugs at the time of overdosing, with crack being the main drug (37.0%). Fifty-four percent were assisted by ambulance personnel, 56.8% were taken to accident and emergency or hospital, 38.1% left accident and emergency or hospital before being released, and 35.1% were given Naloxone.

CONCLUSION

Structural interventions are needed that seek to modify the social and contextual risks for overdose, increased access to treatment programmes, and trials of novel interventions for crystal methamphetamine users.