Rapid decline rather than absolute level of HBsAg predicts its seroclearance in untreated chronic hepatitis B patients from Taiwanese communities.

BackgroundHBsAg clearance leads to favorable outcomes in chronic hepatitis B (CHB) patients. Hepatitis B surface antigen (HBsAg) levels <200 IU/mL with HBsAg decline >0.5 log10 IU/mL in one year have been reported predictive of HBsAg loss. This study aimed to use the REVEAL-HBV cohort to validate and simplify this prediction rule, and verify whether the simplified algorithm can be used among various clinical subgroups.MethodWe analyzed 707 untreated CHB patients who had 3 or more HBsAg measurements within 5 years prior to HBsAg seroclearance or last visit, greater than 1 year apart from one another. Rapid HBsAg decline was defined as HBsAg decline >0.5 log10 IU/mL in 1 year or >1 log10 IU/mL in 2 years. Sensitivity, specificity, PPV and NPV were compared to assess the predictability of HBsAg seroclearance.ResultsDuring a median follow-up of 10.7 years, 41 of the 707 patients cleared serum HBsAg. HBsAg levels at all measurements were lower (p<0.0001) and HBsAg decline was greater (p<0.0001) in patients with seroclearance compared with non-seroclearance patients. The predictive accuracy of predicting 1-year HBsAg loss using only the rapid decline algorithm (sensitivity=0.4412, specificity=0.9792, PPV=0.5172, NPV=0.972) was the same as the model combining rapid HBsAg decline and HBsAg levels <200 IU/mL. The simplified algorithm including only the rapid decline performed similarly among various levels of HBsAg, HBV DNA and ALT, and was independent of inactive carrier state.ConclusionHBsAg decline >0.5 log10 IU/mL/year was a practical predictor of HBsAg seroclearance within one year in our community-based untreated cohort.