Estimating HIV and HCV prevalence among people who inject drugs in 5 Ukrainian cities using stratification-based respondent driven and random sampling.

Background: Ukraine, a country of 45.5 million people, has one of the most volatile HIV and HCV epidemics in the world. In this paper, we estimate the prevalence of HIV and HCV among PWID in five Ukrainian cities.

Methods: A cross-sectional study was conducted in 2014-2015, based on stratified hybrid sampling with random and respondent driven sampling in five cities: Kyiv, Odesa, Mykolaiv, Dnipro and Lviv. Using data on HIV and HCV antibody testing from 1613 respondents, we evaluate selection bias in the sampling methods by analyzing spatial and network patterns of sampling processes. We develop and apply inverse probability weights in order to estimate the HIV and HCV prevalence in each city, as well as in the overall sample.

Findings: The aggregate HIV prevalence for the five cities is 35.1% (95% CI: 29.5%-38.5%) but this varied considerably by city: in Kyiv the HIV prevalence is 26.6% (95% CI: 20.3.8%-33.4%), in Odesa - 38.2% (95% CI: 29.8% and 47.1%), in Mykolaiv - 42.0% (95% CI: 34.3%-49.2%), in Dnipro - 58.8% (95% CI: 52.2%-65.8%), and in Lviv 24.6% (95% CI: 18.8%-30.8%). The aggregate HCV prevalence estimate for the five cities is 58.6% (95% CI: 54.9%-61.7%). The highest HCV prevalence is estimated in Kyiv - 84.8% (95% CI: 78.5%-90.1%). HCV prevalence in Odesa is the lowest and estimated to be 36.5% (95% CI: 29.5%-45.1%), in Mykolaiv - 49.1% (95% CI: 41.5%-57.0%), in Dnipro - 56.1% (95% CI: 50.3%-63.4%) and in Lviv 38.5% (95% CI: 31.8%-45.0%).

Conclusions: Monitoring behavioral and health outcomes of PWID on a regular basis is necessary for determining prevention and treatment priorities for HIV and HCV infections in Ukraine and elsewhere. The heterogeneity of the local epidemics provides insights into the best prevention and treatment strategies to be deployed in low-resource settings.