Determination of the reduction in gastric acidity necessary to prevent pathological oesophageal reflux in patients with gastro‐oesophageal reflux disease treated with a proton pump inhibitor

Summary Background : In subjects with gastro‐oesophageal reflux disease treated with a gastric antisecretory agent, the extent to which gastric acidity needs to be reduced to prevent pathological oesophageal acid exposure is not known. Methods : Gastric and oesophageal pH were measured in 26 healthy subjects and in 59 subjects with gastro‐oesophageal reflux disease. In 27 of the subjects with gastro‐oesophageal reflux disease, pH was also recorded on days 1, 2 and 8 of treatment with 20 mg omeprazole and 20 mg rabeprazole in a randomized, two‐way, cross‐over fashion. Results : Receiver operating characteristic analysis was used to determine values for the integrated oesophageal acidity and time oesophageal pH≤4 that gave optimal cut‐off points for distinguishing between normal and pathological oesophageal reflux. Using these cut‐off points, we found that the probability of no pathological oesophageal reflux (Y) could be best fitted by an exponential equation, Y = a(e–bX) + c, where a, b and c are constants and X is the value of the integrated gastric acidity. There was close agreement between the predicted and observed percentages of subjects with pathological oesophageal reflux during different days of treatment. Conclusions : In subjects with gastro‐oesophageal reflux disease treated with a proton pump inhibitor, the value of the integrated gastric acidity can predict the likelihood of pathological oesophageal reflux.