Risk factors associated with HIV and hepatitis C virus co-infection among people who inject drugs in Cambodia

Background: Globally, research on the co-infection of the human immunodeficiency virus (HIV) and hepatitis C virus (HCV) among people who inject drugs is growing. However, studies in resource-poor countries remain limited. Therefore, we conducted this study to explore factors associated with HIV/HCV co-infection among people who inject drugs in Cambodia. Methods: This national survey was conducted in 2017 in the capital city and 11 provinces. We used a 'peer-based social network recruitment' method to recruit 286 participants for face-to-face interviews and HIV and HCV testing. A modified Cox proportional hazard model was used to identify risk factors associated with HIV/HCV co-infection. Results: The prevalence of HIV and HCV was 15.4% and 30.4%, respectively. Of the total, 9.4% of the participants were HIV/HCV co-infected, and 61.4% of the HIV-infected participants were co-infected with HCV. About half (56.8%) of the participants tested HIV positive were aware of their HIV status; of whom, 83.3% were on antiretroviral therapy. Only 11.5% of the participants with HCV antibody positivity were aware of their HCV infection status; of whom, 50.0% were on HCV treatment. The adjusted prevalence ratio (APR) of HIV/HCV co-infection was significantly higher among women than among men and among participants who lived on the streets than among those living with their family or relatives. The APR of HIV/HCV co-infection was also significantly higher among participants who had received methadone maintenance therapy than those who had not received it. Conclusions: The prevalence of HIV/HCV co-infection among people who inject drugs in Cambodia was considerably high. Intervention programs are required to increase access to harm-reduction interventions among most marginalized people who inject drugs to prevent HIV and HCV infection. HCV screening services should be expanded in this key population, given its small population size and the availability of directly-acting antiviral agents in the country.