[Comparison of esophageal acid exposure characteristics between reflux oesophagitis and non-erosive reflux diseases].

OBJECTIVES: Comparing the esophageal acid exposure characteristics between reflux oesophagitis (RE) and non-erosive reflux disease (NERD) patients to identify the NERD subgroups. METHODS: One hundred and twenty-eight patients with heartburn and acid regurgitation were evaluated. Esophageal mucosa injury was assessed by gastroscopy. The extent of esophageal acid exposure was determined by ambulatory 24 h esophageal pH monitoring. DeMeester point >/= 15 was taken as positive. RESULTS: Thirty-seven patients were found to have RE (28.9%), 91 were diagnosed as NERD. There was no difference at DeMeester point between RE and NERD (P > 0.05). Patients with RE have more long reflux episodes than NERD patients (8.16 +/- 10.27 vs 3.96 +/- 6.87; P = 0.004). Among NERD patients, 46 (50.5%) had an abnormal pH monitoring (NERD+); another 45 were normal (NERD-). Patients with NERD+ were more likely to demonstrate at positive symptom index (SI > 50%) than those with NERD- (43.5% vs 15.6%; P < 0.001). In NERD- group, patients with a positive SI (NERD-SI+) have more reflux episodes than those with a negative SI (NERD-SI-) (55.29 +/- 24.68 vs 34.87 +/- 24.06; P < 0.05), as well as the fraction time of 24 h that pH < 4 in upright (4.16 +/- 2.98 vs 1.88 +/- 1.60; P < 0.05). Twenty-five RE patients have an abnormal pH monitoring (RE+, 67.6%), another 12 were normal (RE-). RE- patients have a higher median of intra-esophageal and gastric pH than RE+ patients respectively (6.75 +/- 0.42 vs 5.18 +/- 1.32; 2.69 +/- 2.59 vs 1.49 +/- 0.66; P < 0.05). CONCLUSIONS: RE patients have longer reflux episodes than NERD. The symptoms of most gastroesophageal reflux disease patients associate with acid reflux. Acid reflux characteristics and symptom patterns suggest subgroups of NERD patients. The bile or mixed reflux may be involved in the pathogenesis of RE- group.