Hepatitis C is a common infection among injecting drug users and has important implications for general practice. Although several clinical guidelines concerning the infection have been published, their effectiveness has yet to be tested. The aim of this research was to assess the effectiveness of a general practice-based complex intervention to support the implementation of clinical guidelines for hepatitis C management among current or former drug users attending general practice. The study design used was a cluster randomised controlled trial in general practices in the Eastern Regional Health Authority area of Ireland.

Twenty-six practices were randomly allocated within strata to receive the intervention under study or to provide care as usual for a period of 6 months. There was screening for patients attending general practice for methadone maintenance treatment for hepatitis C and referral of anti-HCV antibody positive patients to a specialist hepatology department for assessment. The research concluded that at study completion, patients in the intervention group were significantly more likely to have been screened for hepatitis C than those in the control group, odds ratio adjusted for clustering 3.76 (95% confidence interval [CI] = 1.3 to 11.3) and this association remained significant after adjusting for other potentially confounding variables, using multiple logistic regression, with the odds ratio adjusted for clustering 4.53 (95% CI = 1.39 to 14.78). Although anti-HCV antibody positive patients in the intervention group were more likely to have been referred to a hepatology clinic, this was not statistically significant (P = 0.06).