Relationship of severity of gastroesophageal reflux disease with gastric acid secretory profile and esophageal acid exposure during nocturnal acid breakthrough: A study using 24-h dual-channel pH-metry

Objective. In patients with gastroesophageal reflux disease (GERD), refluxed gastric juice can damage the esophagus, and hence the more acidic the juice, the more the expected damage. Nocturnal acid breakthrough (NAB) is known to occur in GERD patients on treatment with proton-pump inhibitors (PPIs); however, whether this causes esophageal acidification and symptoms is controversial. The aims of this study were to investigate the relationship between gastric acid and the severity of GERD and the esophageal acidification and symptoms during NAB. Material and methods. Patients with GERD were evaluated using endoscopy (graded according to the Los Angeles (LA) classification), manometry and 24-h dual-channel pH-metry for esophageal and gastric acid profile and follow-up pH-metry while on PPIs for NAB. Results. In 61 patients (39.2 +/- 12.8 years, 40 M) the endoscopic grading was endoscopy negative (ENRD) in 19 (32%), endoscopic (ERD) in 40 (68%), (LA-A in 25, 42.4%, LA-B in12, 20.3%, peptic stricture in 2, 3.4%, and Barrett's esophagus in 1, 1.7%) and 2 patients were unclassified. Patients in the different groups had comparable gastric acid profiles, though esophageal acid exposure was different (LA-B and above versus ENRD, p=0.007; LA-B and above versus LA-A, p=0.003). Patients with NAB (7/18, 39%) had lower gastric pH than patients without NAB (p=0.003) though average esophageal pH and esophageal acid exposure were comparable. Frequency of nocturnal symptoms was comparable in patients with or without NAB (2/7 versus 3/11, p=NS). Lower esophageal sphincter (LES) pressure was negatively correlated with average gastric pH. Conclusions. Although severity of GERD is related to esophageal acid exposure, it does not correlate to gastric acid. No difference was found in esophageal acid exposure and nocturnal symptoms in patients with or without NAB.