Hepatitis B surface antigen level complements viral load in predicting viral reactivation in spontaneous HBeAg seroconverters.

Background And Aims: The level of hepatitis B surface antigen (HBsAg) has been shown to complement hepatitis B virus (HBV)-DNA level in predicting disease progression in hepatitis B e antigen (HBeAg)-negative patients, especially those with low viral loads. Whether this finding could be seen in spontaneous HBeAg seroconverters remains unclear.

Methods: A retrospective cohort of 390 Taiwanese spontaneous HBeAg seroconverters with a mean follow-up period of 7.4 years was enrolled. The relationships between HBV-DNA/HBsAg levels and HBeAg-negative hepatitis/active viral replication (HBV-DNA level ≥ 2000 IU/mL) were investigated.

Results: In the overall cohort, serum HBV-DNA level served as a better predictor for HBeAg-negative hepatitis compared with HBsAg level. However, in those with HBV-DNA level < 2000 IU/mL, a higher HBsAg level was associated with a higher risk of HBeAg-negative hepatitis (P = 0.015). Multivariate analysis showed the hazard ratio of HBsAg level ≥ 1000 IU/mL versus < 1000 IU/mL was 4.1 (95% confidence interval: 1.3-13.6). When using the end-point of active viral replication, HBsAg ≥ 1000 IU/mL remained as an independent risk factor, with a hazard ratio of 2.5 (95% confidence interval: 1.1-5.9).

Conclusions: In spontaneous HBeAg seroconverters with HBV-DNA level < 2000 IU/mL, HBsAg level ≥ 1000 IU/mL is associated with increased risks of HBeAg-negative hepatitis and active viral replication. Combining HBV-DNA < 2000 IU/mL and HBsAg level < 1000 IU/mL may be used to define minimal viral activity.