This thesis investigated how virologic and serologic kinetics of the hepatitis B virus (HBV) could influence the natural history and treatment of chronic hepatitis B (CHB). Virologic kinetics were described in the first five studies, with serologic kinetics being described in the next five. The first study delineated the HBV DNA profiles of 1,400 treatment-naive Asian CHB patients. Increasing viremia was noted with increasing age, highlighting the large therapeutic demand in Asian patients with hepatitis B e antigen (HBeAg)-negative CHB. The second study analyzed the association between viral load and liver histology in 319 patients, showing HBV DNA levels to have strong association with HBeAg-negative disease severity. The next three studies investigated the efficacy of baseline and on-treatment HBV DNA levels in predicting clinical outcomes in 117, 165 and 222 patients on telbivudine, lamivudine plus adefovir and entecavir respectively. Absolute on-treatment HBV DNA levels at week 12 or 24 predicted favorable outcome with telbivudine and lamivudine / adefovir therapy, while excellent viremic suppression with very low rate of resistance development was shown in the entecavir study. The following three studies examined the role of serum HBsAg measurements in different disease phases of CHB. First, histology specimens of 140 HBeAg-positive patients were analyzed together with HBsAg levels. High HBsAg titers (>25,000 IU/mL) were found to be predictive of insignificant fibrosis. In the next study involving 300 treatment-naive HBeAg-negative patients stratified by their viral loads, combination of low HBsAg and HBV DNA levels predicted significant HBsAg decline. This is followed by a study comparing HBsAg levels of 203 CHB patients achieving HBsAg seroclearance with 203 age- and sex-matched controls over a 3-year period. Serum HBsAg <200 IU/mL and a significant annual HBsAg reduction were found to be predictive of HBsAg seroclearance. The penultimate study investigated the usage of two novel HBV serologic markers, linearized HBsAg and hepatitis B core-related antigen, in 329 CHB patients achieving HBsAg seroclearance with a conventional HBsAg assay. More than 40% of patients had seropositivity to one or both serologic tests. Finally, the last study of this thesis investigated and compared the changes in serum HBsAg, intrahepatic HBV DNA and covalently closed circular DNA (cccDNA) after 1 year of nucleoside analogue therapy. Minimal changes in both serum HBsAg and intrahepatic cccDNA were noted after 1 year of therapy, but in patients with a significant decline in serum HBsAg levels, there was a corresponding significant reduction in cccDNA. This series of studies illustrated how the monitoring of serum HBV DNA and HBsAg levels could assist in optimizing management strategies for CHB. / published_or_final_version / Medicine / Master / Doctor of Medicine

Thesis (M. Med. Sc.)--University of Hong Kong, 2010. / Includes bibliographical references (p. 51-58).

Thesis (M.Res.(Med.))--University of Hong Kong, 2003. / Includes bibliographical references (leaves 68-77) Also available in print.

Thesis (Ph. D.)--University of Hong Kong, 2009. / Includes bibliographical references (leaves 157-186). Also available in print.

published_or_final_version / Medicine / Master / Master of Medical Sciences

Objetivo : Determinar los factores de riesgo asociados a la transmisión del virus de la Hepatitis B (VHB) en el Centro Médico Naval durante el período de estudio. Material y métodos : Estudio de casos y controles. Se evaluaron los pacientes hospitalizados en la Sala de Enfermedades Transmisibles con el diagnóstico de Síndrome ictérico mas hipertransaminasemia ( TGO y/o TGP > 500 u/l ). Los factores de riesgo reportados entre los sujetos infectados con el VHB (B+); fueron comparados con los sujetos no infectados (B-), mediante el análisis bivariado y multivariado. Resultados : Un total de 74 sujetos fueron evaluados serológicamente para VHB, de los cuales 37 fueron positivos ( 35 infección aguda y 2 infección no aguda ). Los sujetos B+ fueron en su mayoría de sexo masculino y tuvieron como factor de riesgo mas significativo una hospitalización previa ( OR:13.33 ). Además se describen los cuadros clínicos y exámenes de laboratorio encontrados en ambos grupos. Conclusión : La fuerte asociación encontrada entre hepatitis B y hospitalización previa, sugiere que la transmisión horizontal nosocomial tiene un rol protagónico en la transmisión del VHB en el Centro Médico Naval.

Objetivo : Determinar los factores de riesgo asociados a la transmisión del virus de la Hepatitis B (VHB) en el Centro Médico Naval durante el período de estudio. Material y métodos : Estudio de casos y controles. Se evaluaron los pacientes hospitalizados en la Sala de Enfermedades Transmisibles con el diagnóstico de Síndrome ictérico mas hipertransaminasemia ( TGO y/o TGP > 500 u/l ). Los factores de riesgo reportados entre los sujetos infectados con el VHB (B+); fueron comparados con los sujetos no infectados (B-), mediante el análisis bivariado y multivariado. Resultados : Un total de 74 sujetos fueron evaluados serológicamente para VHB, de los cuales 37 fueron positivos ( 35 infección aguda y 2 infección no aguda ). Los sujetos B+ fueron en su mayoría de sexo masculino y tuvieron como factor de riesgo mas significativo una hospitalización previa ( OR:13.33 ). Además se describen los cuadros clínicos y exámenes de laboratorio encontrados en ambos grupos. Conclusión : La fuerte asociación encontrada entre hepatitis B y hospitalización previa, sugiere que la transmisión horizontal nosocomial tiene un rol protagónico en la transmisión del VHB en el Centro Médico Naval.

Objectives To systematically review all studies HBV screening and vaccination health behaviour according to the Health Belief Model theoretical framework including perceived susceptibility, severity, barriers and benefits, cues to action and self-efficacy. Methodology The literature search used PUBMED, MEDLINE, CINAHL plus, Wan Fang database, and Chinese Journal Net with English and Chinese language. About 73 studies (PUBMED: 33 MEDLINE: 10, CINAHL plus: 3, Wan Fang database: 16, Chinese journal net: 11) in total were identified; after applying the inclusion and exclusion criteria, 11 studies met the criteria and in the final analysis. The target group included high infection rate groups (pregnant women, unprotected sexual behaviour, and immigrant group) and illness groups (chronic Hepatitis B and Hepatitis B virus carriers). Results and Discussion HBV screening and vaccination behaviour were determined by perceived the susceptibility, perceived severity, perceived barriers and benefits, and cues to action. The self-efficacy was seldom designed in the questionnaire of the reviewed articles. The Health belief model was a useful model for explaining HBV screening and vaccination behaviour. Screening- and vaccination-related beliefs of the screening and vaccination vary by high risk groups. From the review more attention to self-efficacy and perceived control may improve vaccination uptake. There were contrast results with the social economic characteristics, such as age, gender, income, in determining the HBV screening and vaccination behaviour. Conclusion and Implication As the policy maker, health care providers need to develop specific interventions paying attention to the different aspects of the Health Belief Model to improve the perceived of Hepatitis B virus. / published_or_final_version / Public Health / Master / Master of Public Health

published_or_final_version / Medicine / Master / Master of Philosophy

Thesis (M. Phil.)--University of Hong Kong, 2008. / Includes bibliographical references (leaves 94-113) Also available in print.