Tung CH, et al. - Using Taiwan’s Longitudinal Health Insurance Database 2005, a retrospective cohort study was conducted to investigate the relationship between interferon-based therapy (IBT) and the risk of rheumatoid arthritis (RA) in patients infected with hepatitis C virus (HCV). For this investigation, 18,971 subjects with HCV infection between 1 January 1997 and 31 December 2012 were involved. The findings from the present study suggested that IBT might lessen the risk of RA and contributes to growing evidence that HCV infection had a role in the pathogenesis of RA.