Hepatitis C virus prevalence and associated risk factors among Indigenous Australians who inject drugs

Objective: To examine factors associated with hepatitis C virus (HCV) infection among a national sample of Indigenous and non-Indigenous people who inject drugs (PWID) in Australia. Methods: Respondents were recruited from Australia's Needle Syringe Program Survey; an annual bio-behavioural surveillance project that monitors HCV antibody prevalence among PWID. Data from 2006-2015 were de-duplicated to retain only one record where individuals participated in >1 survey round. Univariate and multivariable logistic regression examined demographic characteristics and injection-related behaviours associated with exposure to HCV. Results: Among 17,413 respondents, 2,215 (13%) were Indigenous Australians. Compared to their non-Indigenous counterparts, Indigenous respondents were significantly more likely to be exposed to HCV infection (53% vs. 60% respectively, p<0.001). Among Indigenous respondents, HCV antibody positivity was independently associated with a history of imprisonment (Adjusted Odd Ratio [AOR] 2.13, 95%CI 1.73-2.64), opioid injection (AOR 1.53, 95%CI 11.43-2.16), recruitment in a metropolitan location (AOR 1.27, 95%CI 1.02-1.59), engagement in opioid substitution therapy (AOR 2.83, 95%CI 2.23-3.59) and length of time since first injection (p<0.001). Conclusion: Indigenous PWID are more likely to be exposed to HCV infection than their non-Indigenous counterparts. Implications for public health: Increased access to culturally sensitive harm reduction programs is required to prevent primary HCV infection and reinfection among Indigenous PWID. Given recent advances in HCV treatment, promotion of treatment uptake among Indigenous PWID may reduce future HCV-related morbidity and mortality.