Systematic review and meta-analysis to estimate the burden of fatal and non-fatal overdose among people who inject drugs

Background: People who inject drugs (PWID) have high overdose risk. To assess the burden of drug overdose among PWID in light of opioid epidemic-associated increases in injection drug use (IDU), we estimated rates of non-fatal and fatal overdose among PWID living in Organization for Economic Cooperation and Development (OECD) countries using data from 2010 or later. Methods: PubMed, Psych Info, and Embase databases were systematically searched to identify peer-reviewed studies reporting prevalence or rates of recent (past 12 months) fatal or non-fatal overdose events among PWID in OECD countries. Data were extracted and meta-analyzed using random effects models to produce pooled non-fatal and fatal overdose rates. Results: 57 of 13,307 identified reports were included in the review, with 33/57 studies contributing unique data and included in the meta-analysis. Other (24/57) studies presented overlapping data to those included in meta-analysis. The rates of non-fatal and fatal overdose among PWID in OECD countries were 24.74 per 100 person years (PY) (95% CI: 19.86 - 30.83; n=28; I2=98.5%) and 0.61 per 100 PY (95% CI: 0.32 - 1.16; n=8; I2=93.4%), respectively. The rate of non-fatal overdose was 27.79 in North American countries, 25.71 in Canada, 28.59 in the U.S., and 21.44 in Australia. Conclusion: These findings suggest there is a fatal overdose for every 40 non-fatal overdose events among PWID in OECD countries. The magnitude of overdose burden estimated here underscores the need for expansion of overdose prevention and treatment programs and serves as a baseline estimate for monitoring success of such programs.