The modified glucose clearance test: A novel non-invasive method for differentiating non-erosive reflux disease and erosive oesophagitis

Background: Impaired salivary secretion has been reported to cause abnormal acid clearance from the oesophagus in gastro-oesophageal reflux disease (GERD). However, few studies have explained the differences between non-erosive reflux disease (NERD) and erosive oesophagitis (EO) with respect to salivary secretion. Aim: To elucidate these differences, we measured salivary secretion by using the modified glucose clearance test (mGCT). Methods: All subjects completed endoscopic examinations, the frequency scale for the symptoms of GERD questionnaire and the mGCT comprising a resting GCT (measured as RGC time) and a chewing-stimulated GCT (SGC time). Results: Resting glucose clearance time was 18.5 min in control group and significantly longer in NERD and EO groups (28.5 and 39.0 min respectively). SGC time was 6.1 min in control group and 7.2 min in NERD group and significantly longer in EO group (10.2 min) than in the control and NERD groups. Conclusions: In the EO group, both resting and stimulated salivary secretions were less than in control group. However, in the NERD group, resting salivary secretion was decreased, but stimulated salivary secretion was similar to that of the control group. Therefore, these results may help in explaining the differences in the pathogenesis of NERD and EO.