Chronic Hepatitis C Virus Infection Is Associated with the Development of Rheumatoid Arthritis: A Nationwide Population-Based Study in Taiwan

OBJECTIVE The association between chronic hepatitis virus infection and rheumatoid arthritis (RA) remains debatable. This nationwide population-based cohort study assessed the risk of RA among patients with a chronic infection of hepatitis B and/or C virus. MATERIALS AND METHODS We used data extracted from the claims of 1,000,000 randomly sampled individuals covered under the Taiwan National Health Insurance program. Among the 49,892 persons identified in 2000-2010 with chronic hepatitis virus infection, 35,652 had chronic HBV infection alone, 10,253 had chronic HCV infection alone, and 3,987 had chronic HBV/HCV dual infections. The comparison cohort comprised 199,568 persons matched on sex, age and calendar year without chronic hepatitis virus infection. All study participants were free of RA at baseline and traced through 2011 with new RA cases identified. RESULTS After adjusting for covariates, chronic HCV infection alone was significantly associated with an increased risk for RA (hazard ratio (HR)  = 2.03, 95% confidence interval (CI)  = 1.27-3.22). The increased risk for RA among participants with chronic HCV infection remained significant after restricting the analysis to those who were prescribed disease-modifying anti-rheumatic drugs. The corresponding HR for the overall sample was 1.89 (95% CI  = 1.15-3.11). However, HBV carriers did not appear to be at a significantly higher risk for RA. CONCLUSION Our data imply that chronic HCV infection is associated with RA development.