Patients with lower hepatitis B surface antigen levels are more likely to achieve surface antigen seroclearance, according to recent results.
Researchers compared the hepatitis B surface antigen (HBsAg) and HBV DNA serum levels of 203 hepatitis B e antigen (HBeAg)-negative patients who experienced spontaneous HBsAg seroclearance with 203 matched controls. Samples were obtained at 3 years, 2 years, 1 year and 6 months before seroclearance, and also at the time of HbsAg loss.
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At all tested points, median HBsAg and HBV DNA levels were less in the seroclearance group than among controls (P<.001 for all). Median HBsAg levels among the seroclearance group were 23.5 IU/mL at 3 years, 3.51 IU/mL at 2 years, 0.524 IU/mL at 1 year and 0.146 IU/mL at 6 months (P<.001 for decline). HBsAg levels in controls also declined gradually at a slower rate than the seroclearance group (P=.006). A gradual decline was also observed in median HBV DNA levels in the seroclearance group (131 IU/mL to 20 IU/mL, P<.001), but not among controls (1,920 IU/mL to 1,792 IU/mL, P=.414) (P<.001 for difference between groups).
HBsAg serum levels were found through AUROC analysis to be a predictor of HBsAg seroclearance (AUROC=0.833; 95% CI, 0.792-0.873), with HBsAg log reduction the second-most predictive factor (AUROC=0.802; 95% CI, 0.755-0.849). Ideal cutoff values for predicting seroclearance were less than 200 IU/mL for HBsAg level and 0.5 log IU/mL per year for log reduction. An annual 0.5-log HBsAg reduction was found to be a predictor for seroclearance among patients with serum HBsAg levels of 200 IU/mL or more. Attempts to combine HBV DNA and HBsAg levels in analysis did not improve the AUC for predicting seroclearance.
“Both absolute and serial measurements of serum HBsAg would offer valuable clinical data in determining the probability of long-term seroclearance,” the researchers concluded. “These may also serve as good indicators for the consideration of treatment duration and cessation for [chronic HBV].”