Theme: Epidemiology & Public Health Research Year: 2023
Background:
Research suggests people who inject drugs (PWID) are at excess risk of acquiring sexually transmitted infections (STI). In the context of increasing STI incidence globally, understanding sexual behaviour, STI testing uptake, and STI prevalence among PWID is critical.
Methods:
We conducted searches of the peer-reviewed and grey literature, date limited from January 2008 to April 2022. Sexual behaviour and STI testing uptake were based on self-report, while only data from studies which conducted STI testing were used to estimate STI prevalence. Where sufficient data were available, regional and global estimates weighted by population size were generated using random effects meta-analysis.
Results:
The availability of data varied greatly by region. We estimated that 14.9% (95% confidence interval [95% CI] 8.1-24.3) of PWID have recently (i.e., in the past year) engaged in sex work, while 20.6% (95% CI: 12.3-31.0) reported recent sex with a casual partner without a condom. Globally, we estimated the prevalence of syphilis among PWID was 4.37% (2.95-6.85), ranging from 0.258% (1.96-6.76) in North America to 12.0% (9.57-14.7) in South Asia. The prevalence of genital herpes, chlamydia and gonorrhea was estimated to be 19.2% (95% CI: 16.0-22.7), 4.74% (95% CI: 1.90-10.5), and 1.17% (0.097-5.45), respectively. Data on human papilloma virus and trichomoniasis were each only reported in one study. Data on recent STI testing uptake were sparse and highly heterogenous; the pooled estimate was 23.4% (95% CI: 11.9-37.3).
Conclusion:
To the authors’ knowledge, these are the first global prevalence estimate of STIs among PWID, which may serve as a baseline for monitoring disease burden. Future prevalence estimates would benefit from an increase in quality and quantity of data.