HIV prevalence among people who inject drugs (PWID) and related factors in Iran: a systematic review, meta-analysis and trend analysis.

AIMS: In Iran, injecting drug use has been the major route of human immunodeficiency virus (HIV) transmission. In order to control the HIV epidemic, a harm reduction program was initiated and has been expanded in recent years. The aim of this study was to provide an updated estimate of HIV prevalence among people who inject drugs (PWID) in Iran, investigate prevalence differences over time and assess prevalence correlates. DESIGN: A comprehensive systematic review was undertaken in the international, regional and national bibliographic databases in November 2018 and extensive contacts with authors were made. For studies conducted before 2005, we used data from a previous published systematic review. SETTING: All studies conducted in Iran were included. Recruitment settings included anywhere except studies conducted in infectious diseases wards or HIV counseling centers. PARTICIPANTS: PWID with any definition utilized in the studies. Thirty-six studies were included, which were conducted in 24 of 31 provinces with a sample size of 22 160 PWID. MEASUREMENTS: We included studies that had performed HIV testing and had a confirmed diagnosis of HIV through repeating the enzyme-linked immunosorbent assay (ELISA) or Western immunoblot assay (WB). Pooled prevalence of HIV was calculated for the total sample and for different subgroups, by available socio-demographic and behavioral factors. For assessing the trend of HIV prevalence over time, a linear meta-regression model was fitted separately for before 2007 and during 2007 and afterwards. FINDINGS: The pooled prevalences of HIV before 2007 and in 2007 and afterwards were 14.3% [95% confidence interval (CI) = 9.8-18.9] and 9.7% (95% CI = 7.6-11.9), respectively. HIV prevalence increased until 2005-06 and then slowly declined until 2009-10, which was not significant. Prevalence of HIV was significantly higher in PWID above age 25 years, and in those with history of imprisonment and history of needle/syringe-sharing. HIV prevalence was higher in men than in women, but the difference was insignificant. CONCLUSION: The prevalence of HIV among people who inject drugs in Iran decreased after 2006 which could, at least in part, be attributed to the development of extensive harm reduction programs in the country.