IDDF2024-ABS-0177 Natural history and prognosis of chronic hepatitis B patients in the indeterminate phase

Background In chronic hepatitis B patients, an indeterminate phase exists outside the typical predefined phases. Our study investigates this indeterminate phase's natural history and prognosis, focusing on antiviral treatment outcomes. Methods We conducted a retrospective cohort study to compare the risk of transitioning to the Immune Active phase in patients with indeterminate chronic hepatitis B and the incidence of adverse liver outcomes (hepatocellular carcinoma and/or cirrhosis) between untreated patients with indeterminate chronic hepatitis B (at baseline and throughout follow-up) and those who received treatment, following standard AASLD 2018 guidance. Results Inverse probability of treatment weighting (IPTW) was utilized to balance the groups of treated and untreated patients. Following IPTW adjustment, the 5-, 10-, and 12-year risk of transitioning to Immune Active was 11.8%, 12.3%, and 13.5% among treated patients (n=294), compared to 39.2%, 43.6%, and 44.8% among untreated patients (n=334), respectively (PP=0.004) (IDDF2024-ABS-0177 Figure 2).In the multivariable analysis, antiviral therapy remained an independent predictor of a reduced risk of transitioning to Immune Active (aHR 0.238, 95% CI 0.162-0.351, PPConclusions The phase of indeterminate chronic hepatitis B patients changes frequently, and antiviral therapy can reduce the risk of transitioning to Immune Active as well as the incidence of developing hepatocellular carcinoma and/or cirrhosis.