Incidence, Factors, and Patient-Level Data for Spontaneous HBsAg Seroclearance: A Cohort Study of 11,264 Patients
Yee Hui Yeo, Tai‐Chung Tseng, Tetsuya Hosaka, Chris Cunningham, James Yan Yue Fung, Hsiu J. Ho, Min‐Sun Kwak, Huy N. Trinh, Teerapat Ungtrakul, Ming‐Lung Yu, Mariko Kobayashi, An K. Le, Linda Henry, Jiayi Li, Jian Zhang, Tassanee Sriprayoon, Donghak Jeong, Tawesak Tanwandee, Ed Gane, Ramsey Cheung, Chun‐Ying Wu, Anna S. Lok, Hyo-Suk Lee, Fumitaka Suzuki, Man‐Fung Yuen, Jia‐Horng Kao, Hwai‐I Yang, Mindie H. Nguyen
Abstract
INTRODUCTION: Spontaneous hepatitis B surface antigen (HBsAg) seroclearance, the functional cure of hepatitis B infection, occurs rarely. Prior original studies are limited by insufficient sample size and/or follow-up, and recent meta-analyses are limited by inclusion of only study-level data and lack of adjustment for confounders to investigate HBsAg seroclearance rates in most relevant subgroups. Using a cohort with detailed individual patient data, we estimated spontaneous HBsAg seroclearance rates through patient and virologic characteristics. METHODS: We analyzed 11,264 untreated patients with chronic hepatitis B with serial HBsAg data from 4 North American and 8 Asian Pacific centers, with 1,393 patients with HBsAg seroclearance (≥2 undetectable HBsAg ≥6 months apart) during 106,192 person-years. The annual seroclearance rate with detailed categorization by infection phase, further stratified by hepatitis B e antigen (HBeAg) status, sex, age, and quantitative HBsAg (qHBsAg), was performed. RESULTS: The annual seroclearance rate was 1.31% (95% confidence interval: 1.25-1.38) and over 7% in immune inactive patients aged ≥55 years and with qHBsAg <100 IU/mL. The 5-, 10-, 15-, and 20-year cumulative rates were 4.74%, 10.72%, 18.80%, and 24.79%, respectively. On multivariable analysis, male (adjusted hazard ratio [aHR] = 1.66), older age (41-55 years: aHR = 1.16; >55 years: aHR = 1.21), negative HBeAg (aHR = 6.34), and genotype C (aHR = 1.82) predicted higher seroclearance rates, as did lower hepatitis B virus DNA and lower qHBsAg (P < 0.05 for all), and inactive carrier state. DISCUSSION: The spontaneous annual HBsAg seroclearance rate was 1.31%, but varied from close to zero to about 5% among most chronic hepatitis B subgroups, with older, male, HBeAg-negative, and genotype C patients with lower alanine aminotransferase and hepatitis B virus DNA, and qHBsAg independently associated with higher rates (see Visual Abstract, Supplementary Digital Content 2, http://links.lww.com/CTG/A367).