Association of serum hepatitis B surface antigen with hepatitis B virus DNA and hepatic function in patients with chronic hepatitis B.

BACKGROUND: The relationship between hepatitis B surface antigen (HBsAg) concentrations, hepatitis B virus (HBV) DNA levels, and hepatic function in individuals with chronic hepatitis B (CHB) remains incompletely characterized. AIM: To examine the association of serum HBsAg concentrations with HBV DNA levels and hepatic function parameters in patients with CHB. METHODS: A total of 110 individuals with CHB admitted to Kunming Third People's Hospital between January 2023 and January 2025 were enrolled as the observation group, whereas 70 age- and sex-matched healthy individuals served as the control group. Fasting peripheral venous blood (5 mL) was collected from all participants. Serum HBsAg and HBV DNA levels (in the observation group), along with hepatic function markers, including total bilirubin (TBIL), aspartate aminotransferase (AST), and alanine aminotransferase (ALT), were measured in both groups. Pearson correlation analysis was used to assess the association between serum HBsAg levels and HBV DNA, TBIL, AST, and ALT levels in patients with CHB. Receiver operating characteristic (ROC) curve analysis was conducted to determine optimal cutoff values of HBsAg for predicting high viral load (HBV DNA ≥ 105 IU/mL) and significant liver injury (ALT ≥ 2 × upper limit of normal [ULN]). RESULTS: HBsAg levels differed significantly across CHB phases: Immune tolerance (IT) phase (4.62 ± 1.51 lgIU/mL), immune clearance (IC) phase (3.84 ± 1.16 lgIU/mL), low replication (LR) phase (2.99 ± 0.66 lgIU/mL), and HBV e antigen-negative hepatitis (ENH) phase (3.40 ± 0.69 lgIU/mL). Corresponding HBV DNA levels were highest in the IT phase (7.41 ± 1.83 log copies/mL), followed by the IC phase (6.03 ± 1.92 log copies/mL), ENH phase (3.89 ± 1.23 log copies/mL), and LR phase (2.55 ± 1.00 log copies/mL). All hepatic function parameters in patients with CHB were significantly elevated compared to the healthy controls. Pearson correlation analysis showed significant positive associations between serum HBsAg levels and HBV DNA, TBIL, AST, and ALT levels. ROC analysis revealed that an HBsAg cutoff > 4.09 lgIU/mL predicted HBV DNA ≥ 105 IU/mL (high viral load) with 88.57% sensitivity, 78.67% specificity, and an area under the curve (AUC) of 0.868 (P < 0.001), while a cutoff > 4.07 lgIU/mL predicted ALT ≥ 2 × ULN (significant liver injury) with 69.70% sensitivity, 90.91% specificity, and an AUC of 0.821 (P < 0.001). CONCLUSION: Serum HBsAg, a noninvasive serological marker, holds significant clinical value in CHB management by aiding in the stratification of viral burden and the prediction of hepatic impairment.