BackgroundHepatitis B surface antigen (HBsAg) loss is regarded as a pivotal criterion for assessing functional cure in patients diagnosed chronic hepatitis B (CHB). We conducted the research to investigate the real-world performance of HBsAg seroconversion in sustaining HBsAg loss.MethodsThis retrospective analysis confirmed 295 patients who attained HBsAg loss through combination therapy involving nucleos(t)ide analogues (NAs) and pegylated interferon alpha (peg-IFNα). Employing Kaplan–Meier estimates method to conduct survival analysis. The forest plot was used to visualize the results of multivariate Cox regression, and selected variables were included in the nomogram.ResultsHBsAg seroreversion was observed in 45 patients during follow-up periods, with a lower recurrence risk in patients with HBsAg seroconversion at the end of peg-IFNα therapy (EOT) (10.3% vs 37.3% at 96-week, P < 0.0001). Moreover, the sustainability of hepatitis B surface antibody (anti-HBs) in participants continuing therapy after HBsAg seroconversion was superior to those discontinued prematurely (72.5% vs 54.5% at 96 weeks, P = 0.012). Additionally, the former group was also relatively less likely to experience HBsAg reversion during long-term observation (8.4% vs 14.3% at 96 weeks, P = 0.280). Hepatitis B envelope antigen (HBeAg) status, anti-HBs status and consolidation treatment screened by multivariable analysis were utilized to construct a predictive model for HBsAg reversion. The concordance index(C-index = 0.77) and calibration plots indicated satisfactory discrimination and consistency of nomogram.ConclusionsHBsAg seroconversion was beneficial for sustaining functional cure in patients treated with peg-IFNα. Continuing consolidation therapy after HBsAg seroconversion also contributed to maintain HBsAg seroconversion and improve the durability of HBsAg loss. The nomogram illustrated its efficacy as a valuable instrument in showcasing survival probability of functional cure.