Clinical Consequences of Hepatitis B Surface Antigen Loss in Chronic Hepatitis B Infection: A Systematic Literature Review and Meta-Analysis

Background and Aims: Functional cure, which requires sustained hepatitis B surface antigen (HBsAg) loss after treatment cessation, is currently the optimal treatment endpoint for chronic hepatitis B virus infection. We performed a systematic literature review (SLR) and meta-analyses to assess the association between HBsAg loss and long-term clinical outcomes. Methods: We performed a SLR of scientific literature published in Medline and Embase reporting the incidence of cirrhosis, hepatic decompensation (HD), hepatocellular carcinoma (HCC), liver-related mortality (LRM), and all-cause mortality (ACM) in relation to HBsAg status. Bayesian hierarchical commensurate prior meta-analyses synthesized evidence on the association between HBsAg loss and each outcome. Results: Thirty-eight studies, comprising 50,354 patients with 350,734 patient-years of follow-up, were included in the meta-analyses, reporting on cirrhosis (n = 12), HD (n = 12), HCC (n = 36), LRM (n = 12), and ACM (n = 16). Pooled incidence rate ratios (IRRs; vs HBsAg persistence) and respective credible intervals (Crls) were 0.28 (0.060-1.070) for cirrhosis, 0.13 (0.013-0.38) for HD, 0.27 (0.11-0.53) for HCC, 0.17 (0.028-0.61) for LRM, and 0.64 (0.24-1.17) for ACM. Single-predictor-adjusted IRRs remained consistent with those from the primary analyses for all outcomes except cirrhosis and LRM. Outcome incidence rates were modified by selected study, patient and infection characteristics, but trended in the same direction of reduced risk after loss. Conclusion: Overall, HBsAg loss was associated with a reduced risk of most clinically relevant outcomes. While the magnitude of the effect differed across subgroups, the direction of the association remained similar. Our results validate the need to develop new strategies to achieve HBsAg loss.