Importance of reflux symptoms in functional dyspepsia

The relation between symptom severity in gastro-oesophageal reflux disease (GORD) and quantitated oesophageal acid reflux is variable. Furthermore, when oesophageal acid exposure lies within the conventional normal range, the cause of the symptoms is unknown. This prospective study evaluated 24 hour ambulatory oesophageal pH profiles in relation to objective symptom scores in 100 dyspeptic patients who were free from ulcer and gall stones. Twenty patients had raised oesophageal acid exposure and reflux symptoms consistent with GORD, and 80 had oesophageal pH profiles within the conventional normal range. Forty four of the 80 had severe or moderate reflux symptoms and were classified as having reflux like functional dyspepsia (RFD); 36 had minimal or absent reflux symptoms, and were categorised as having non-reflux dyspepsia (NFD). While oesophageal pH profiles lay within the conventional normal range in both functional dyspepsia subgroups, patients with RFD had consistently greater acid exposure values as follows: mean (SEM) total oesophageal acid exposure time, RFD 16.2 (2.56) min v NFD 9.05 (2.0) min (p < 0.03); percentage of time with pH < 4, RFD 1.4 (0.2) v NFD 0.8 (0.2) (p < 0.03); DeMeester scores, RFD 12.8 (0.5) v NFD 11.4 (0.4) (p < 0.03). The RFD group had a pain/reflux event correlation of 23.8 (5.3)% v 8.1 (3.7)% for the NFD group (p < 0.01). This study shows that patients with RFD have oesophageal acid exposure that lies below the diagnostic threshold for GORD, but exceeds that of patients with NFD. The high pain/reflux event correlation in RFD, suggests that subthreshold oesophageal acid exposure may be associated with troublesome reflux symptoms.