Higher end-of-treatment HBsAg levels is associated with later onset but not severe relapse in HBeAg-negative chronic hepatitis B patients stopping antivirals.

Background: Quantitative hepatitis B surface antigen (qHBsAg) level at end-of-treatment (EOT) predict clinical relapse (CR) after nucleos(t)ide analogues (Nuc) in chronic hepatitis B(CHB) patients. It is unclear if higher EOT qHBsAg leads to earlier onset or more severe off-Nuc CR.
Aim: This large cohort study investigates the association between EOT qHBsAg and CR onset/severity.
Methods: This study enrolled HBeAg-negative CHB patients who had achieved undetectable HBV DNA for over 1 year after receiving Nuc therapy before discontinuation. The EOT qHBsAg level was categorised into three groups: <100, 100-999, ≥1000 IU/mL. The study assessed the predictability of qHBsAg levels for CR, and analysed and compared the incidence, time to onset and severity of CR among these three groups.
Results: Patients with higher EOT qHBsAg showed a higher incidence of CR (≥1000, 100-999, <100 IU/mL: 73%, 65%, and 38%, p < 0.01) but a later onset of CR (median time to CR: 35, 33 and 27 weeks, p < 0.01). The predictabilities of EOT qHBsAg for CR were greater in patients aged <50-year-old or with genotype C than in those aged ≥50-year-old or with genotype B. There's no correlation between EOT qHBsAg level and ALT folds at CR (Pearson correlation coefficient: r = -0.03, p = 0.35). EOT qHBsAg was neither a predictor for severe hepatitis flare nor a predictor for hepatic decompensation.
Conclusions: Predictability using EOT qHBsAg levels for CR differed in subgroups of age and genotypes. Higher EOT qHBsAg levels correlate with higher incidence but later onset of CR. No correlation between EOT qHBsAg and relapse severity was observed.
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