Association of antiviral therapy with reduced disease progression in chronic Hepatitis B patients: Results from a nation-wide cohort study.

Background and Aims: Although effective treatment in terms of inducing virological and biochemical response for chronic hepatitis B (CHB) is available, its effect on the clinical course of the disease has not yet been accurately estimated. Objective of this study was to evaluate the effect of antiviral therapy and its type [interferon +/-nucleos(t) ide analogs (NAs) vs. NAs] on the occurrence of a clinical event (liver decompensation, liver transplant, hepatocellular carcinoma and death from a liver-related cause) in CHB patients. Methods: The study population was derived from the HEPNET-Greece, a nationwide cohort study aimed to evaluate the current epidemiological course of viral hepatitis. To account for time-dependent confounding, Cox marginal structural models were used to analyze data. Results: Thirty out of 2,125 eligible patients experienced a clinical event during their follow-up. When comparing treated to untreated individuals, the hazard ratio (HR) for a clinical event was 0.39 (95% CI: 0.16-0.98; p =0.044) in the whole sample, whereas there were indications of a more intense effect in the subgroup of patients with cirrhosis at presentation (HR =0.16, 95% CI: 0.02-1.21; p =0.075). The effect of Interferon initiated treatment was not significantly different of that of NAs. There was some evidence, albeit not statistically significant, of a protective treatment effect on hepatocellular carcinoma development (HCC). Conclusions: Data from observational studies can provide useful inference, provided they are analyzed appropriately. The current study has shown that the available treatment options for CHB offer a significant clinical benefit to CHB infected individuals.