The relation between symptom severity in gastro-oesophageal reflux dis
ease (GORD) and quantitated oesophageal acid reflux is variable. Furth
ermore, when oesophageal acid exposure lies within the conventional no
rmal range, the cause of the symptoms is unknown. This prospective stu
dy 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 ex
posure and reflux symptoms consistent with GORD, and 80 had oesophagea
l pH profiles within the conventional normal range. Forty four of the
80 had severe or moderate reflux symptoms and were classified as havin
g reflux like functional dyspepsia (RFD); 36 had minimal or absent ref
lux symptoms, and were categorised as having non-reflux dyspepsia (NFD
). While oesophageal pH profiles lay within the conventional normal ra
nge in both functional dyspepsia subgroups, patients with RFD had cons
istently greater acid exposure values as follows: mean (SEM) total oes
ophageal 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 hav
e oesophageal acid exposure lies below the diagnostic threshold for GO
RD, but exceeds that of patients with NFD. The high pain/reflux event
correlation in RFD, suggests that subthreshold oesophageal acid exposu
re may be associated with troublesome reflux symptoms.