HBsAg spontaneous seroclearance in a cohort of HBeAg-seronegative patients with chronic hepatitis B virus infection

Loss of hepatitis B surface antigen (HBsAg) is considered to reflect the resolution of a hepatitis B virus (HBV) infection. Patient characteristics and various seromarkers were evaluated to characterize factors predicting spontaneous HBsAg loss in a cohort of HBeAg-seronegative patients with presumed chronic HBV infection. Relationships between seromarkers and HBsAg loss were assessed annually and after 6 years using binary logistic regression. Among the 634 participants, 117 (18.45%) cleared HBsAg after 6 years, with a 3.08% annual seroclearance rate. Baseline HBsAg levels and platelet (PLT) counts were predictors of HBsAg seroclearance. The HBsAg level predicted HBsAg seroclearance better than the PLT count (area under the receiver operating characteristic curve (AUROC): HBsAg, 0.965 (95%CI, 0.947-0.980) versus PLT count, 0.617 (95%CI, 0.561-0.669); P < 0.001). A cutoff HBsAg level of 10 IU/ml at baseline predicted spontaneous HBsAg seroclearance at 6 years with a diagnostic accuracy of 93.4%, a sensitivity of 87.2%, a specificity of 94.8%, a positive predictive value of 79.1%, and a negative predictive value of 97.0%. HBsAg seroclearance may occur more commonly than expected. A serum HBsAg level <10 IU/ml and PLT count were accurate predictors of clearance.