Change in injecting behaviour among people treated for hepatitis C virus: the role of intimate partnerships

Injecting behaviour in people who inject drugs is the main risk factor for hepatitis C virus (HCV) infection. Psychosocial factors such as having a partner who injects drugs and living with other drug users have been associated with increases in injecting risk behaviour. This study aimed to investigate changes in injecting behaviour during treatment for HCV infection whilst exploring the role of psychosocial factors on patients’ injecting behaviour. Eradicate-C was a single-centred clinical trial (ISRCTN27564683) investigating the effectiveness of HCV treatment within the injecting drug-using population between 2012 and 2017. A total of 94 participants completed up to 24 weeks of treatment, with social and behavioural measures taken at different intervals throughout treatment. Data for 84 participants were analysed retrospectively to explore mechanisms of potential behavioural changes which had occurred during treatment. Injecting frequency reduced significantly between baseline (week 1) and every 4-weekly interval until week 26. Not being on opiate substitution therapy (OST) was associated with a statistically significant decrease in injecting frequency, χ ² (1) = 10.412, P = 0.001, as was having a partner who also used drugs, in particular when that partner was also on treatment for HCV infection, Z = −2.312, P = 0.021. Treating a hard-to-reach population for HCV infection is not only possible, but also bears health benefits beyond treatment of HCV alone. Enrolling couples on HCV treatment when partners are sero-concordant has shown enhanced benefits for reduction in injecting behaviour. Implications for practice are discussed.