[Dynamic changes of HBsAb and its predictive value in patients with chronic hepatitis B receiving antiviral therapy for clinical cure].

<b>Objective:</b> To explore the predictive value of hepatitis B surface antibody (HBsAb) quantitative level for achieving hepatitis B surface antigen (HBsAg) seroclearance and serological conversion in patients with chronic hepatitis B (CHB) treated with nucleos(t)ide analogs (NAs) or interferon (IFN). <b>Methods:</b> A two-center prospective cohort study was conducted, including CHB patients from Nanfang Hospital Southern Medical University and Eastern Theater General Hospital treated with NAs and IFN. All patients were followed up once every three to six months. Basic clinical information and test results were collected at each follow-up. The presence or absence of HBsAg seroclearance and serological conversion rate was evaluated. HBsAg serological conversion was defined as HBsAg quantification continuously below the detection limit (<0.05 IU/mL) at two detection time points at least six months apart. HBsAg serological conversion was defined as HBsAb positivity (≥10 IU/L) at the same time as the first HBsAg seroclearance. The Kruskal-Wallis test was used to compare the quantitative data of multiple groups, and the Wilcoxon rank-sum test was used to compare the data between groups. The chi-square test was used for the count data, and the Fisher exact test was used when the chi-square test was not met. Univariate and multivariate Cox analysis was used to determine the predictors of the study endpoints, and stepwise regression was used for variable screening. <b>Results:</b> A total of 2 266 CHB cases were included, of which 86.5% (1 959/2 266) were NA antiviral-received population. The median treatment duration before baseline was 10.5 (2.5, 37.6) months, and the baseline HBsAg quantification was 3.1 (2.6, 3.5) log₁₀ IU/mL. A total of 68 cases (3.0%) had HBsAg seroclearance, and 44 cases (1.9%) achieved serological conversion after 85.0 (62.7, 97.3) months of prospective follow-up. The level and positivity rate of HBsAb showed a progressive increase 36 months before and significantly after HBsAg seroclearance. Cox regression analysis results showed that baseline HBsAb level was an independent predictor of HBsAg serological conversion (<i>HR</i>=2.26, <i>P</i>=0.002) in the overall population, especially in the subgroup with HBsAg between 100 and 1 000 IU/mL, suggesting HBsAb level had important predictive value. In addition, the serological conversion development rate was significantly higher in the GOLDEN model favourable patients than in the unfavourable patients (11.5% vs. 0, <i>P</i><0.001). <b>Conclusion:</b> The baseline HBsAb quantitative level can predict HBsAg seroclearance and serological conversion for patients with CHB receiving antiviral treatment, which is of significant value in long-term treatment monitoring.