Alimentary Pharmacology and Therapeutics
Higher lifetime chance of spontaneous surface antigen loss in hepatitis B carriers with genotype C infection T.-C. Tseng*,†, C.-J. Liu‡,§, C.-L. Chen§, W.-T. Yang¶,**, H.-C. Yang‡,††, T.-H. Su‡,§, C.-C. Wang*,**, S. F.-T. Kuo‡‡, C.-H. Liu‡,§, P.-J. Chen‡,§, D.-S. Chen‡,§ & J.-H. Kao‡,§,¶,§§
*Division of Gastroenterology, Department of Internal Medicine, Taipei Tzuchi Hospital, The Buddhist Tzuchi Medical Foundation, Taipei, Taiwan. † School of Medicine, Tzu Chi University, Hualien, Taiwan. ‡ Division of Gastroenterology, Department of Internal Medicine, National Taiwan University College of Medicine and National Taiwan University Hospital, Taipei, Taiwan. § Graduate Institute of Clinical Medicine, National Taiwan University College of Medicine and National Taiwan University Hospital, Taipei, Taiwan. ¶ Hepatitis Research Center, National Taiwan University College of Medicine and National Taiwan University Hospital, Taipei, Taiwan. **Master of Public Health Degree Program, National Taiwan University, Taipei, Taiwan. †† Department of Microbiology, National Taiwan University College of Medicine and National Taiwan University Hospital, Taipei, Taiwan. ‡‡ St Vincent’s Hospital, Melbourne, Vic., Australia. §§ Department of Medical Research, National Taiwan University College of Medicine and National Taiwan University Hospital, Taipei, Taiwan.
Correspondence to: Dr J.-H. Kao, Graduate Institute of Clinical Medicine, National Taiwan University College of Medicine, 1 Chang-Te St., Taipei 10002, Taiwan. E-mail: [email protected]
Publication data Submitted 6 October 2014 First decision 18 November 2014 Resubmitted 13 January 2015 Resubmitted 20 February 2015 Accepted 2 March 2015 EV Pub Online 23 March 2015
SUMMARY Background Clearance of hepatitis B surface antigen (HBsAg) indicates clinical control of hepatitis B virus (HBV) infection. However, little is known about the impact of viral genomic variations on HBsAg loss. Methods We explored the association between viral genomic factors and HBsAg loss in 2121HBeAg-negative patients. HBV pre-core stop codon (1896) and basal core promoter (BCP) (1762/1764) sequences were determined in patients with HBV DNA ≥200 IU/mL (N = 1693). The effect of HBV genotype on HBsAg loss was further validated in the whole cohort of 3445 HBsAg carriers. Results The cumulative lifetime (age 28–75 years) incidence of HBsAg loss was 50.4% in 2121 HBeAg-negative patients. We found that genotype C, but not pre-core stop codon or BCP mutants, was associated with HBsAg loss. Compared to genotype B patients, genotype C patients had higher lifetime chance of HBsAg loss, with hazard ratio of 1.8 (95% conﬁdence interval: 1.4–2.4). Multivariable analysis showed that male sex, elevated ALT levels, lower serum HBV DNA and HBsAg levels, and genotype C infection were associated with higher chance of HBsAg loss independently. We then performed sensitivity analysis, which re-included HBeAg-positive, cirrhotic and treatment-experienced patients, and conﬁrmed the robustness of our results in 3445 HBsAg carriers. Conclusion Genotype C infection, compared to genotype B, is associated with a higher lifetime chance of HBsAg loss in Asian HBV carriers. Aliment Pharmacol Ther 2015; 41: 949–960
This article was accepted for publication after full peer-review.
ª 2015 John Wiley & Sons Ltd doi:10.1111/apt.13170
T.-C. Tseng et al. INTRODUCTION Hepatitis B virus (HBV) infection is a global health problem, resulting in more than one million deaths per year. Patients with chronic HBV infection have 25–40% estimated lifetime risk of developing adverse outcomes such as cirrhosis and hepatocellular carcinoma (HCC).1, 2 In the meantime, there is an annual incidence of 1–2% for hepatitis B surface antigen (HBsAg) clearance in hepatitis B e antigen (HBeAg)-negative patients, implicating a sustained immune control of HBV infection with favourable outcomes.3–5 In clinical practice, two quantiﬁable viral factors, including HBV DNA and HBsAg levels, have been used used to evaluate viral activity.4 Both factors are closely related with risk of HCC and chance of HBsAg clearance.6–9 In addition to viral activity, HBV genotypes and mutants are also important determinants for disease progression in HBV carriers.10–12 Patients with HBV genotype C infection are shown to carry a higher risk of HCC development than those with genotype B infection.6, 10, 12 Emergence of pre-core stop codon (PC) mutant (G1896A) or basal core promoter (BCP) mutant (A1762T/G1764A) also affects HCC and cirrhosis development.11–13 However, the relationship between spontaneous HBsAg loss and HBV genotype or common viral mutants remains largely unknown. To address these interesting and important issues, we conducted a large cohort study with a long-term followup.7, 8, 14, 15 In the present study, we ﬁrst determined viral genomic factors and analysed their relationships with HBsAg loss. We then performed sensitivity analysis to test whether the correlation between HBV genotype and HBsAg loss still held true in the whole cohort of HBsAg carriers. MATERIALS AND METHODS Patient cohort Figure 1 shows the inclusion and exclusion criteria of patients in the ‘Elucidation of Risk fActors for DIsease Control or Advancement in Taiwanese hEpatitis B carriers’ (ERADICATE-B) study. In short, 3947 HBsAg-positive patients aged above 28 years were consecutively enrolled between 1985 and 2000. We ﬁrst excluded patients with evidence of hepatitis C virus (HCV) or hepatitis D virus (HDV) co-infection, patients without adequate serum samples for analysis, and two who cleared HBsAg after receiving liver transplant. Second, we excluded 411 patients who were diagnosed with cirrhosis at baseline because such patients are recommended for 950
anti-viral therapy bycurrent practice guidelines,16–18 390 patients who received anti-viral therapy before the end of follow-up because anti-viral treatment would alter the natural outcomes,19 and 523 HBeAg-positive patients, who were in the early stage of disease thus had very limited chance to clear HBsAg.20 The remaining 2121 HBeAgnegative patients were then included for analysis. To avoid selection bias introduced by the multiple selections, we reincluded the patients excluded in the second step, including cirrhotic, treatment-experienced and HBeAg-positive patients, for a sensitivity analysis to validate our ﬁndings in the whole cohort of HBsAg carriers. All enrolled patients gave informed consents as approved by the research ethical committee of National Taiwan University Hospital.
Data collection Patients were tested for serological markers (HBsAg, HBeAg, anti-HBe, anti-HCV and anti-HDV), liver enzymes and alpha-fetoprotein at baseline. Throughout their followup, liver enzymes and alpha-fetoprotein were assayed every 3–6 months. Serum samples collected at each visit were stored at 20 °C until analysis. Abdominal ultrasonography using high-resolution and real-time scanners was performed every 3–6 months from the enrolment. Deﬁnition and diagnosis of spontaneous HBsAg loss, cirrhosis and HCC Spontaneous HBsAg loss was deﬁned as two consecutive HBsAg levels