Comparison of the main epidemiological and virological characteristics of the 193 patients (current cohort) and 299 patients (general cohort [8]) at study entry.

nd = not done. In the general cohort [8] HBsAg, HDV RNA and HBV DNA were not quantified.
na = not applicable. In the original cohort [8], mean age and median follow-up were calculated from the first evidence of chronic liver disease. In the current cohort, mean age and follow-up were calculated at entry into the current study, corresponding to first access to our unit as well as time of collection of the first serum sample available for testing.
*The proportion of cirrhosis was slightly higher in the current cohort because we are a referral centre for both HBV infection and advanced liver diseases. Therefore, we often received from other Italian institutions patients with HBV related cirrhosis before the diagnosis of HDV coinfection was made.