[Distribution characteristics of serum HBsAg levels in Chinese patients with chronic hepatitis B based on CR-HepB].

<b>Objective:</b> To determine the distributions of serum HBsAg level in treatment-naive or treatment-experienced chronic hepatitis B (CHB) patients. <b>Methods:</b> Based on the China Registry of Hepatitis B (CR-HepB), a nationwide hospital-based electronic platform, treatment-naive or treatment-experienced CHB patients who receive nucleos(t)ide analog (NA) therapy were enrolled in our study. We collected patients' clinical characteristics, including demographic, virological and biochemical data. The distributions of HBsAg levels in those two groups were summarized with counts and percentages. Continuous variables were expressed as median (interquartile range, IQR) or mean±SD. <b>Results:</b> A total of 13 505 treatment-naive CHB patients and 6 309 patients with previous NAs therapy were enrolled in the final analysis. The proportion of patients in those two groups with serum HBsAg<100 IU/ml, <500 IU/ml, <1 500 IU/ml or HBsAg level not lower than 1 500 IU/ml, 3 000 IU/ml or 8 000 IU/ml were 10.51% vs. 12.88%, 28.47% vs. 29.84%, 46.85% vs. 52.07%, 53.15% vs. 47.93%, 38.17% vs. 31.77%, 15.62% vs. 10.39%, respectively. HBsAg levels tended to decrease gradually with the duration of antiviral therapy: the percentage of patients with HBsAg levels below 100 IU/ml increased from 12.73% at less than 3 years of treatment to 26.92% at≥10 years of treatment, whereas the percentage of patients with HBsAg levels of 3 000 IU/ml or 8 000 IU/ml and above decreased from 34.66% to 23.08% and from 12.19% to 5.77%, respectively. <b>Conclusions:</b> Our investigation manifested the distribution of the serum HBsAg in treatment-naive CHB patients and patients who received previous NAs treatment. As the duration of antiviral therapy is prolonged, the HBsAg level tends to decrease gradually.