Background and aimHepatitis C virus (HCV) infection poses a major public health challenge in Indian settings due to its huge population and easy transmissibility of HCV among individuals who inject drugs (PWID, which is increasing in India). The National AIDS Control Organization (NACO), India has started the Opioid Substitution Therapy (OST) centers to improve the health status of opioid dependent PWID and prevent the spread of HIV/AIDS among them. We conducted a cross-sectional study to find out the HCV sero-positive status and associated determinants in patients attending the OST centre in the ICMR-RMRIMS, Patna.Materials and methodsWe utilized the routinely collected (as a part of the National AIDS Control Program) and de-identified data from the OST center from 2014 to 2022 (N = 268). We abstracted the information for exposure variables (such as socio-demographic features and drug history) and outcome variable (HCV serostatus). The association of exposure variables with HCV serostatus was examined using robust Poisson regression.ResultsAll the enrolled participants were male and the prevalence of HCV seropositivity was 28% [95% confidence interval (CI): 22.7% - 33.8%)]. There was a rising prevalence of HCV seropositivity with number of years of injection use (p-trend <0.001) and age (p-trend 0.025). Approximately, 6.3% participants were injecting drugs for >10 years and reported the maximum prevalence of HCV seropositivity (47.1%, 95% CI: 23.3%-70.8%). In adjusted analyses, being employed compared to unemployed patients [adjusted prevalence ratio (aPR) = 0.59; 95% CI: 0.38–0.89]; graduated patients compared to illiterate patients [aPR = 0.11; 95% CI: 0.02–0.78]; and patients with education up to higher secondary compared to illiterate patients [aPR = 0.64; 95% CI: 0.43–0.94] had significantly lesser HCV seropositivity. A-one year increase in injection use [aPR = 1.07; 95% CI: 1.04–1.10] was associated with 7% higher prevalence of HCV seropositivity.ConclusionsIn this OST center-based study of 268 PWIDs residing in Patna, ~28% of patients were HCV seropositive, which was positively associated with years of injection use, unemployment, and illiteracy. Our findings suggest that OST centers offer an opportunity to reach a high-risk difficult to reach group for HCV infection and thus support the notion of integrating HCV care into the OST or de-addiction centres.