Integrated acidity and the pathophysiology of gastroesophageal reflux disease

OBJECTIVES: The aim of this study was to demonstrate that integrated esopha geal and gastric acidity values, calculated from 24-h pH recordings, can pr ovide more precise quantitative temporal data than the conventional pH para meters historically associated with gastroesophageal reflux disease (GERD) investigations. METHODS: Esophagogastroduodenoscopy results and pH tracings from 20 GERD su bjects with greater than or equal to 10% esophageal acid contact time were studied. Integrated gastric and esophageal acidity were calculated from tim e-weighted average hydrogen ion concentrations at each second of the 24-h r ecording period. RESULTS: Integrated esophageal acidity correlated with grade of esophagitis . Two quite distinct GERD subtypes were identified, with either a monophasi c or biphasic pattern of integrated esophageal acidity. "Biphasic" subjects differed from "monophasic" subjects in terms of magnitude and pattern of i ntegrated esophageal acidity. Although both groups had significant integrat ed nocturnal gastric acidity, only the biphasic GERD subjects had concomita nt increases in nocturnal integrated esophageal acidity. Esophagitis grade was correlated with magnitude rather than pattern of integrated esophageal acidity, and it was possible to calculate a reflux coefficient that seems t o provide an estimate of the quantitative motor disturbance present in GERD . CONCLUSIONS: Integrated esophageal and gastric acidity provide quantitative measures of GERD pathophysiology acid, compared to conventional pH paramet ers, should enhance evaluation of therapeutic interventions. (C) 2001 by Am . Cell. of Gastroenterology.