Epidemiology and management of gastro-esophageal reflux disease and functional dyspepsia in the Hong Kong Chinese

Abstract

Gastro-esophageal Reflux Disease and Functional Dyspepsia are extremely common gastrointestinal conditions internationally and in East Asia, with prevalence rates of the two conditions being 10% and between 7-15%, respectively. East Asia includes China, the most populous country in the world, meaning that vast numbers of subjects are affected by these conditions chronically. Despite the scale of the problem in East Asia, relatively few studies have examined in a robust fashion whether GERD prevalence rates are rising in East Asia and the implications this has on the economics costs, both direct and indirect, of caring for patients with these conditions. Furthermore, the armamentarium available for non-erosive reflux disease and in particular, functional dyspepsia, is limited especially if treatments not supported by scientific evidence are excluded. Previous studies on the temporal trend of GERD in the East Asia and Asia-Pacific region have been hampered with issues of sampling methodology, use of different questionnaires and issues with the translation which make comparisons between countries and over time difficult. This thesis addresses these issues in a large cross-sectional population-based study and finds that GERD prevalence rates have significantly risen in the Hong Kong Chinese population, and that subjects with GERD consume disproportionately more healthcare services and experience more lost productivity than subjects without GERD. Finally, three double-blinded, placebo-controlled, randomized clinical studies were performed to investigate pharmacologic options for gastro-esophageal reflux disease and functional dyspepsia. One study was performed to determine the efficacy of proton pump inhibitors on non-erosive reflux disease as the availability of clinical studies to answer this question in East Asia is scant. This study finds that proton pump inhibitors at a standard dose, once daily are efficacious in the treatment of non-erosive reflux disease. The two final clinical studies were the first studies of their kind to investigate the use of selective serotonin selective reuptake inhibitors, an antidepressant and rifaximin in the treatment of functional dyspepsia. The intriguing results of the antidepressant study provoked further research by other researchers, whilst the strongly positive results of rifaximin in the treatment of functional dyspepsia, has added another treatment option to an area with few effective treatments. This body of work has spawned many other fascinating research questions which will no doubt be the subject of future research projects at this institution and others in the near future.