Association between antiviral treatment and extrahepatic outcomes in patients with hepatitis C virus infection

Objective: To elucidate the association between antiviral therapy and extrahepatic outcomes in individuals infected with HCV. Methods: This nationwide cohort study screened 293 480 Taiwanese residents with HCV infection and excluded those with substantial comorbidity. A total of 12 384 eligible patients who had received pegylated interferon plus ribavirin between 1 October 2003 and 31 December 2010 were enrolled in the treated cohort; they were matched 1: 2 with 24 768 untreated controls in the propensity score and post-diagnosis treatment-free period. The incidences of end-stage renal disease (ESRD), acute coronary syndrome (ACS), ischaemic stroke and catastrophic autoimmune diseases were calculated after adjustment for competing mortality. Results: The treated and untreated cohorts were followed up for a mean (±SD) duration of 3.3 (±2.5) and 3.2 (±2.4) years, respectively, until 31 December 2011. The calculated 8-year cumulative incidences of ESRD, ACS, ischaemic stroke and autoimmune catastrophes between treated and untreated patients were 0.15% vs 1.32% (p<0.001), 2.21% vs 2.96% (p=0.027), 1.31% vs 1.76% (p=0.001) and 0.57% vs 0.49% (p=0.816), respectively. Multivariate-adjusted Cox regression revealed that antiviral treatment was associated with lower risks of ESRD (HR 0.15; 95% CI 0.07 to 0.31; p<0.001), ACS (HR 0.77; 95% CI 0.62 to 0.97; p=0.026) and ischaemic stroke (HR 0.62; 95% CI 0.46 to 0.83; p=0.001), but unrelated to autoimmune catastrophes. These favourable associations were invalid in incompletely treated patients with duration <16 weeks. Conclusions: Antiviral treatment for HCV is associated with improved renal and circulatory outcomes, but unrelated to catastrophic autoimmune diseases.