Differences of esophageal acid exposure and pathogenesis for different subtypes of gastroesophageal reflux disease

Objective To compare the characteristics of esophageal acid exposure among subtypes of reflux esophagitis(RE)and non-erosive reflux disease(NERD)and to explore their pathogenesis.Methods A total of 115patients with typical reflux symptoms underwent gastroscopy and esophageal pH monitoring.Results ①26cases(22.6%)of 115patients were RE,the other 89cases were NERD.The abnormal pH monitoring rate(92.3% vs74.2%)and all parameters of pH monitoring including DeMeester score(64.55[128.28]vs 26.60[59.11])in the RE group were significantly higher than those in the NERD group(P 0.05or 0.01).②RE with positive pH monitoring(RE+)subgroup had more the percentage of time that pH4in 24hours(17.6%[38.8%]vs 9.0%[20.3%]),the percentage of time that pH4in recumbent position(18.3%[49.3%]vs 6.5%[18.4%]),long reflux episodes(15.00[19.00]times vs 5.00[8.25]times)and DeMeester score(69.70[120.47]marks vs 35.58[64.97]marks)compared to NERD with positive pH monitoring(NERD+)subgroup(P0.05or0.01).③The majority of parameters of pH monitoring in the moderate and severe RE were significantly higher than those in the mild(P 0.05or0.01).The medians of most parameters of pH monitoring in the mild RE were higher than those in the NERD+subgroup,though without significant difference.④Reflux symptoms were unrelated to abnormal acid reflux in the NERD with negative pH monitoring(NERD-)subgroup.Conclusion Abnormal acid reflux is a major factor in the mucosal injury of RE.The acid exposure of esophagus is heavier,the inflammation is more severe.Reflux symptoms are related to abnormal acid reflux in NERD+subgroup.NERD+ may be a milder form,while RE may be a more severe one in the same spectrum of disease.Visceral hypersensitivity plays a primary role in the pathogenesis of NERD-SI+subgroup.Reflux symptoms are unrelated to acid in the NERD-SI-subgroup.