Injecting risk behaviours amongst people who inject drugs: A global multi-stage systematic review and meta-analysis.

Background: Injecting risk behaviour, such as receptive sharing of injecting equipment and/or re-using one's equipment, is associated with bloodborne virus transmission and infections in people who inject drugs (PWID). We aimed to estimate prevalence and correlates of injecting risk behaviours amongst PWID.

Methods: We conducted a systematic review and meta-analyses to estimate country, regional, and global prevalences of injecting risk behaviours (including sharing or re-using needle/syringe and sharing other injecting equipment). Using meta-regression analyses, we determined associations between study- and country-level characteristics and receptive needle/syringe sharing.

Results: From 61,077 identified papers and reports and 61 studies from expert consutation, evidence on injecting risk behaviours was available for 464 studies from 88 countries. Globally, it is estimated that 17.9% (95%CI: 16.2-19.6%) of PWID engaged in receptive needle/syringe sharing at last injection, 23.9% (95%CI: 21.2-26.5%) in the past month, and 32.8% (95%CI: 28.6-37.0%) in the past 6-12 months. Receptive sharing of other injecting equipment was common. Higher prevalence of receptive needle/syringe sharing in the previous month was associated with samples of PWID with a lower proportion of females, shorter average injecting duration, a higher proportion with ≥daily injecting, and older studies. Countries with lower development index, higher gender inequality and lower NSP coverage had higher proportions reporting receptive needle/syringe sharing.

Conclusions: High levels of injecting risk behaviours were observed amongst PWID globally, although estimates were only available for half of the countries with evidence of injecting drug use. There is a need for better capturing of injecting risk behaviours in these countries to inform implementation of harm reduction services and evaluate potential impacts of interventions to reduce risk.