Pronounced decline of serum HBsAg in chronic hepatitis B patients with long-term effective nucleos(t)ide analogs therapy

AIMS: This study aims to investigate the kinetics of serum HBsAg levels in chronic hepatitis B patients with long-term nucleos(t)ide analogs (NAs) therapy. METHODS: HBsAg II Quant Assay. RESULTS: In this cohort, serum HBsAg levels reduced from 3.80 log10 IU/mL at baseline to 2.72 log10 IU/mL at year 8 (p < .001), and the percentage of patients with HBsAg <1000 IU/mL increased from 14.9% at baseline to 55.3% at year 8 (p < .001). The reduction of serum HBsAg did not differ significantly between patients stratified by baseline virological parameters and type of antiviral agents. But as compared to patients without HBeAg seroconversion, HBsAg levels were significant lower in patients with HBeAg seroconversion (3.19 vs. 2.47 log10 IU/mL at year 8, p = .001). As compared to patients with slow (0-1 log10 IU/mL) or steady HBsAg(≤0 log10 IU/mL) decline at year 1, patients with a rapid HBsAg (≥1 log10 IU/mL) decline had a significantly lower HBsAg levels from year 2 to 8. However, Cox regression analysis showed that only absolute HBsAg levels at year 1 was an independent predictor of subsequent HBsAg <1000 IU/mL at year 8 of antiviral therapy(HR 0.242, p = .004). CONCLUSION: Pronounced HBsAg declines could be achieved in patients after long-term effective therapy with NAs, and on-treatment low serum HBsAg level at year 1 might be a predictor of serum HBsAg <1000 IU/mL at year 8.