Hepatitis B e antigen loss in adults and children with chronic hepatitis B living in North America: A prospective cohort study.

Hepatitis B e antigen (HBeAg) is a soluble viral protein in plasma of patients with hepatitis B virus infection. HBeAg loss is an important first stage of viral antigen clearance. We determined the rate and predictors of HBeAg loss in a North American cohort with chronic hepatitis B viral infection (CHB). Among children and adults with CHB and without HIV, HCV or HDV co-infection enrolled in the Hepatitis B Research Network prospective cohort studies, 819 were HBeAg positive at their first assessment (treatment naïve or >24 weeks since treatment). Of these, 577 (200 children, 377 adults) were followed every 24-48 weeks. HBeAg loss was defined as first HBeAg-negative value; sustained HBeAg loss was defined as ≥2 consecutive HBeAg-negative values ≥24 weeks apart. During a median follow-up of 1.8 years, 164 participants experienced HBeAg loss, a rate of 11.4 (95% CI, 9.8-13.3) per 100 person-years. After adjustment for confounders, HBeAg loss rate was significantly higher in males than females, in older than younger individuals, in Whites or Blacks than Asians, in those with genotype A2 or B versus C, and in those with basal core promoter/pre-core mutations versus wild type. Additionally, during follow-up, an ALT flare and a lower quantitative HBsAg, quantitative HBeAg or HBV DNA level predicted higher rates of HBeAg loss. The majority (88%) with HBeAg loss had sustained HBeAg loss. In conclusion, a number of specific demographic, clinical and viral characteristics impacted rate of HBeAg loss and may prove useful in design and interpretation of future therapeutic studies.