METHODS: Collation and review of existing estimates of IDU prevalence and HIV prevalence from published and unpublished documents for the period 1998-2003. The strength of evidence for the information was assessed based on the source and type of study.
RESULTS: Estimates of IDU prevalence were available for 130 countries. The number of IDU worldwide was estimated as approximately 13.2 million. Over ten million (78%) live in developing and transitional countries (Eastern Europe and Central Asia, 3.1 million; South and South-east Asia, 3.3 million; East-Asia and Pacific, 2.3 million). Estimates of HIV prevalence were available for 78 countries. HIV prevalence among IDU of over 20% was reported for at least one site in 25 countries and territories: Belarus, Estonia, Kazakhstan, Russia, Ukraine, Italy, Netherlands, Portugal, Serbia and Montenegro, Spain, Libya, India, Indonesia, Malaysia, Myanmar, Nepal, Thailand, Viet Nam, China, Argentina, Brazil, Uruguay, Puerto Rico, USA and Canada.
CONCLUSIONS: These findings update previous assessments of the number of countries with IDU and HIV-infected IDU, and the previous quantitative global estimates of the prevalence of IDU. However, gaps remain in the information and the strength of the evidence often was weak.
METHODS: We conducted a systematic review searching MEDLINE, Scopus, Web of Science, Cochrane Central Register of Controlled Trials and PsycINFO for studies published from January 2000 to March 2019. Reference lists and conference proceedings were hand-searched. Observational and intervention studies were eligible for inclusion. Risk of bias was assessed using the Risk of Bias in Non-Randomised Studies of Interventions (ROBINS-I) tool. Meta-analyses were conducted using random-effects models.
RESULTS: Of 13 373 records identified, 11 studies from Australia, Europe, Malaysia and the United States were included. All studies had at least a serious risk of bias, largely due to confounding and selection bias, making it difficult to draw causal conclusions from the evidence. Ten studies provided data on the association between current OAT use and recent HIV testing. Six showed a positive association, while four provided little evidence of an association: pooled odds ratio (OR) = 1.71, 95% confidence interval (CI) = 1.28-2.27. Looking at having ever been on OAT and having ever been HIV tested, seven studies showed a positive association and three showed either weak or no evidence of an association: pooled OR = 3.82, 95% CI = 2.96-4.95.
CONCLUSIONS: Opioid agonist therapy may increase uptake of HIV testing among people who inject drugs, providing further evidence that opioid agonist therapy improves the HIV treatment care cascade.