Incidence and Prediction of HBsAg Seroconversion in a Prospective Multi-ethnic HBeAg-Negative Chronic Hepatitis B Cohort.

BACKGROUND & AIMS Achieving HBsAg loss is an important landmark in the natural history of chronic hepatitis B. A more personalized approach to prediction of HBsAg loss is relevant in couseling patients. This study sought to develop and validate a prediction model for HBsAg loss based on quantitative HBsAg levels and other baseline characteristics. METHODS Hepatitis B Research Network (HBRN) is a prospective cohort including 1240 untreated HBeAg-negative patients (1150 adults, 90 children) with median follow-up of 5.5 years. Incidence rates of HBsAg loss and anti-HBs acquisition were determined and a predictor score of HBsAg loss using readily available variables was developed and externally validated. RESULTS Crude incidence rates of HBsAg loss and anti-HBs acquisition were 1.6 and 1.1 per 100 person-years (PY); 67 achieved sustained HBsAg loss for an incidence rate of 1.2 per 100 PY. Increased HBsAg loss was significantly associated with older age, non-Asian race, HBV phenotype (inactive carrier vs others), HBV genotype A, lower HBV DNA levels and lower and greater change in quantitative HBsAg (∆qHBsAg). The HBRN-SQuARe (sex,∆quantHBsAg, age, race) score predicted HBsAg loss over time with AUROC (95% confidence intervals) at 1 and 3 years of 0.99 (95% CI: 0.987-1.00) and 0.95 (95% CI 0.91-1.00), respectively. Validation in another cohort of 1253 HBeAg-negative patients with median follow-up of 3.1 years, HBRN-SQuARe predicted HBsAg loss at 1 and 3 years with AUROC values of 0.99 [0.98-1.00] and 0.88 [0.77-0.99], respectively. CONCLUSION HBsAg loss in predominantly untreated patients with HBeAg-negative chronic hepatitis B can be accurately predicted over a 3-year horizon using a simple validated score (HBRN-SQuARe). This prognostication tool can be used to support patient care and counseling.