The effect of hepatitis C treatment and human immunodeficiency virus (HIV) co-infection on the disease burden of hepatitis C among injecting drug users in Amsterdam.

AIMS: The hepatitis C virus (HCV) disease burden among injecting drug users (IDUs) is determined by HCV incidence, the long latency period of HCV, competing mortality causes, presence of co-infection and HCV treatment uptake. We examined the effect of these factors and estimated the HCV disease burden in Amsterdam. DESIGN: A Markov model was developed, incorporating HCV and human immunodeficiency virus (HIV), and parameterized with data from the Amsterdam Cohort Studies, surveillance studies and literature. SETTING: IDU population of Amsterdam. MEASUREMENTS: HCV infection simulated from its acute phase to HCV-related liver disease (i.e. decompensated cirrhosis and hepatocellular carcinoma). FINDINGS: The HCV prevalence among IDUs in Amsterdam increased to approximately 80% in the 1980s. From 2011 to 2025, the HCV-related disease prevalence will accordingly rise by 36%, from 57 cases (95% range 33-94) to 78 (95% range 43-138), respectively. In total, 945 (95% range 617-1309) individuals will develop HCV-related liver disease. This burden would have been 33% higher in the absence of HIV, resulting in 1219 cases (95% range 796-1663). In Amsterdam, 25% of HIV-negative IDUs receive successful HCV treatment, reducing the cumulative disease burden by 14% to 810 (95% range 520-1120). Further reduction of 36% can be achieved by improving treatment, resulting in 603 cases (95% range 384-851). CONCLUSIONS: The hepatitis C virus burden among injecting drug users in Amsterdam has been reduced by a high competing mortality rate, particularly caused by HIV infection, and to a smaller extent by hepatitis C virus treatment. Improved hepatitis C virus treatment is expected to contribute to reduce the future hepatitis C virus disease burden.