Is functional dyspepsia largely explained by gastro-oesophageal reflux disease?

Functional dyspepsia is a chronic disorder of unknown aetiology. The lack of endoscopic abnormalities in patients with this disorder has led many physicians to believe that gastro-oesophageal reflux disease may be responsible for most symptoms. Our group has addressed this issue, by pathophysiological studies in a large cohort of Dundee patients with persistent dyspeptic symptoms. Peptic ulcer and gallstones were excluded in all patients by appropriate tests. Ambulatory pH monitoring showed oesophageal acid reflux that lay above the conventional diagnostic threshold in approximately 20% of patients. This subset was diagnosed as having gastro-oesophageal reflux disease. In the remainder, moderate or severe reflux-like symptoms were reported by approximately 44% patients, who were categorized as reflux-like functional dyspepsia. Reflux symptoms were mild or absent in 36% patients, who were categorized as non-reflux-like dyspepsia. While oesophageal pH profiles lay within the conventional normal range in both of these functional dyspepsia subgroups, patients with reflux-like functional dyspepsia had significantly greater acid exposure values, including total oesophageal acid exposure time, percentage time at a pH of less than 4.0, DeMeester scores and pain reflux event correlation. Hence patients with reflux-like functional dyspepsia have oesophageal acid exposure that lies below the diagnostic threshold for gastro-oesophageal reflux disease but exceeds that of patients with non-reflux dyspepsia. The high pain/reflux event correlation in reflux-like functional dyspepsia suggests that subthreshold oesophageal acid exposure may be associated with troublesome reflux symptoms.