Trajectories of serum HBsAg during treatment and association with HBsAg loss in children with HBeAg-positive chronic hepatitis B: a latent class trajectory analysis.

Background: The change of serum hepatitis B surface antigen (HBsAg) during treatment are associated with HBsAg loss. However, little is known about the trajectory patterns of HBsAg in early treatment and their relationship with subsequent HBsAg loss. This study aimed to identify trajectories of HBsAg in children with HBeAg-positive chronic hepatitis B (CHB) and investigate the association between trajectory patterns and HBsAg loss.

Methods: A retrospective study was conducted on 166 treatment-naive children with HBeAg-positive CHB. Latent class trajectory analysis was used to identify trajectory groups of serum HBsAg. Cox proportional hazard model was used to assess the association between HBsAg trajectory groups and HBsAg loss.

Results: The median follow-up time was 20.70 (12.54, 34.17) months, and HBsAg loss occurred in 70(42.17%) of all study participants. Using latent class trajectory analysis, HBeAg-positive CHB patients were classified into three trajectory groups: trajectory 1 (sustained stability, 24.70%), trajectory 2 (slow decline, 38.55%), and trajectory 3 (rapid decline, 36.75%), respectively. The median decline levels of HBsAg at the 3-month and 6-month follow-ups were the highest in trajectory 3 (1.08 and 3.28 log10 IU/ml), followed by trajectory 2 (0.27 and 1.26 log10 IU/ml), and no change in trajectory 1. The risk of achieving HBsAg loss was higher in both trajectory 2 (HR, 3.65 [95% CI, 1.70-7.83]) and trajectory 3 (HR, 7.27 [95% CI, 3.01-17.61]), respectively.

Conclusion: Serum HBsAg levels during early treatment can be classified into distinct trajectory groups, which may serve as an additional predictive indicator for HBsAg loss in HBeAg-positive CHB children.