Predicting hepatitis B surface antigen (HBsAg) clearance is important for chronic hepatitis B (CHB) patients receiving pegylated interferon-alfa (Peg-IFN) therapy. We aimed to determine the predictive value of serum hepatitis B core antibody (anti-HBc) for HBsAg clearance. A total of 189 HBeAg-negative CHB patients who received Peg-IFN based therapy were retrospectively included and classified into two groups: nucleos(t)ide analogues (NAs) add-on Peg-IFN group (add-on group, n = 94) and Peg-IFN combined with NAs or Peg-IFN monotherapy group (combination or monotherapy group, n = 95). After 48 weeks of treatment, 27.5% (52/189) and 15.9% (30/189) of patients achieved HBsAg clearance and seroconversion, respectively. Patients in the combination or monotherapy group tended to achieve relatively higher HBsAg clearance (31.6% vs. 23.4%, p = 0.208) and seroconversion (21.1% vs. 10.6%, p = 0.050) rates than those in the add-on group. In combination or monotherapy group, anti-HBc levels at week 12 were lower in patients with HBsAg clearance (9.0 S/CO vs. 9.9 S/CO, p < 0.001) and seroconversion (8.8 S/CO vs. 9.8 S/CO, p < 0.001) than those without. Anti-HBc level at week 12 was an independent predictor of HBsAg clearance and seroconversion. Patients with lower anti-HBc levels at week 12 showed a more significant decline in HBsAg levels during treatment. Combination of anti-HBc at week 12 and baseline HBsAg could identify over 70% of patients who achieved HBsAg clearance after 48 weeks of treatment. In addition to HBsAg, anti-HBc level could be used as a promising marker for selecting HBeAg-negative CHB patients who are more likely to respond to Peg-IFN-based therapy.
