Quantification of hepatitis B surface antigen can help predict spontaneous hepatitis B surface antigen seroclearance.

BACKGROUND AND AIM

The clinical outcomes of hepatitis B virus (HBV) carriers are favorable following hepatitis B surface antigen (HBsAg) seroclearance. The aim of this study was to investigate the clinical course of spontaneous HBsAg seroclearance and the factors predicting it.

METHODS

A total of 423 patients who tested positive for HBsAg and were referred to Chiba University Hospital between January 1985 and April 2008 were included in the study and the following characteristics were analyzed: age, sex, status of hepatitis B e antigen, alanine aminotransferase level, HBV DNA level, number of platelets, HBV genotype, past treatment with interferon, and HBsAg level. When a nucleotide analog was used for treatment, we stopped follow-up. Measurement of HBsAg was performed using the chemiluminescent enzyme immunoassay method and less than 0.03 IU/ml of HBsAg was designated as HBsAg seroclearance.

RESULTS

The study group included 239 men and 184 women and their average age was 40.5 ± 13.8 years. Twenty-five patients achieved HBsAg seroclearance during the follow-up period with an incidence rate of 0.97% per year. Multivariate analysis revealed that HBsAg titer (compared with patients with a low HBsAg level: odds ratio=0.45, 95% confidence interval: 0.29-0.70) at baseline was the only predictive factor for HBsAg seroclearance.

CONCLUSION

HBsAg seroclearance occurred at a frequency of 0.97% per year without the use of a nucleotide analog. HBsAg titer at baseline was the only predictive factor for HBsAg seroclearance.