The effects of needle-sharing and opioid substitution therapy on incidence of hepatitis C virus infection and reinfection in people who inject drugs.

Although high hepatitis C virus (HCV) prevalence has been observed in people who inject drugs (PWID) for decades, research suggests incidence is falling. We examined whether PWIDs' use of opioid substitution therapy (OST) and their needle-and-syringe sharing behaviour explained HCV incidence. We assessed HCV incidence in 235 PWID in Melbourne, Australia, and performed discrete-time survival with needle-sharing and OST status as independent variables. HCV infection, reinfection and combined infection/reinfection incidences were 7·6 [95% confidence interval (CI) 4·8-11·9], 12·4 (95% CI 9·1-17·0) and 9·7 (95% CI 7·4-12·6) per 100 person-years, respectively. Needle-sharing was significantly associated with higher incidence of naive HCV infection [hazard ratio (HR) 4·9, 95% CI 1·3-17·7] but not reinfection (HR 1·85, 95% CI 0·79-4·32); however, a cross-model test suggested this difference was sample specific. Past month use of OST had non-significant protective effects against naive HCV infection and reinfection. Our data confirm previous evidence of greatly reduced HCV incidence in PWID, but not the significant protective effect of OST on HCV incidence detected in recent studies. Our findings reinforce the need for greater access to HCV testing and prevention services to accelerate the decline in incidence, and HCV treatment, management and support to limit reinfection.

The impact of injecting drug use status on hepatitis C-related referral and treatment.

More than 160,000 people are living with chronic hepatitis C virus (HCV) infection in Australia, however, rates of medical treatment are low. The aim of this study is to examine uptake and predictors of HCV-related health care services among a community-based sample of people with HCV. A self-administered questionnaire was completed by a largely non-clinical sample of 362 women and 308 men with HCV living in the state of Victoria. Analyses were performed according to injecting drug use (IDU) status: no history of injecting (non-IDUs), previous history of injecting (past-IDUs) and current (within the last 12 months) history of injecting (current IDUs). Bivariate and multivariate predictors of referral to a specialist liver clinic were also assessed. Fifty-one percent of participants were current IDUs, 33% past-IDUs and 16% non-IDUs. Fifty-two percent of women and 37% of men reported ever being referred to a specialist liver clinic and 18% of women and 20% of men reported previous HCV antiviral therapy. Although there were many factors related to an increased likelihood of referral (e.g. being female, longer time since diagnosis, longer consultation time at diagnosis, experiencing HCV-related symptoms), multivariate analysis revealed that not being a current IDU and seeing a GP specifically for HCV were the most important independent predictors of referral. For those who had been referred to a liver clinic, a history of IDU was associated with a lower chance of receiving antiviral therapy. IDU status is associated with both referral and treatment. The extension of HCV treatment services to involve GPs and drug and alcohol practitioners should be explored as models to improve access to antiviral therapy.