Associated Director Global Epidemiology, Office of Chief Medical Officer, Johnson & Johnson Shanghai, China (People's Republic)
Background: Hepatitis B virus surface antigen (HBsAg) is the glycosylated envelope protein of mature hepatitis B virions and is an important prognostic indicator of response to anti-viral therapy.
Objectives: Hence, we aim to investigate the dynamic change in HBsAg and incidence of HBsAg loss in real world clinical practice.
Methods: We conducted a retrospective cohort study using electronic medical records from Ruijin Hospital, Shanghai Jiaotong University School of Medicine, China. Adult CHB patients with at least 6 months of NA treatment from January 01, 2012 and HBsAg positive at baseline were enrolled. Patients with diagnoses of co-infection or HCC or any other malignancy at baseline were excluded. Patients were followed from the first identified NAs prescription until discontinuation of NAs treatment, end of study period (December 31, 2020), or last electronic medical records, whichever occurred first. The dynamic change of HBsAg were described by the best (lowest) quantified HBsAg (qHBsAg), regarding as a categorical and continuous variable.
Results: The cohort of 4,907 patients was identified among 34,999 patients with CHB who received NA treatment during study period from Jan 01, 2012 to Dec 31, 2020 at Ruijin Hospital. The median age of the cohort was 39 years (IQR 32–52) and 3,266 (66.56%) were male. The serum HBV DNA level was < 2000 IU/mL in 3,017 (62.88%) patients. There were 2,233 (47.73%) patients who were HBeAg negative, and 1,464 (29.83%), 3,443 (70.17%), patients had qHBsAg level ≤1000 IU/ml, >1000 IU/ml at baseline. The median (IQR) qHBsAg test frequency was 1.5 (1-2.2) times annually. 3,916 (79.80) patients were observed qHBsAg reduction during the follow-up period. Among them, 2882 (73.60%) achieved < 0.5 log10 IU/ml decrease, 569 (15.21%) achieved a 0.5–1 log10 IU/ml decrease, 380 (9.70%) achieved a 1–2 log10 IU/ml decrease, and 85 (2.17%) patients achieved a >2 log10 IU/ml decrease. The median duration from the first identified NA treatment to the best qHBsAg test date was 335, 511, 525 and 729 days, respectively. The median (IQR) rate of reduction in HBsAg per year was 0.20 (0.10 – 0.55) log10 IU/ml. Among the rest patients who weren’t observed the qHBsAg reduction, the median increase was 0.08 log10 IU/ml. There were 63 patients who achieved HBsAg loss. The median (IQR) time to HBsAg loss was 737 (245–1327) days. The incidence rate of HBsAg loss was 0.57/100 person-year.
Conclusions: The study showed HBsAg decrease rate is slow and HBsAg loss rarely occurs under NA treatment.
