PH Monitoring in Asymptomatic Individuals and Its Endoscopic Correlates

Abstract

Purpose: To determine the prevalence, in asymptomatic individuals, of significant esophageal acid exposure and to correlate esophageal acid exposure to the endoscopic and histologic appearance of the esophagus. Methods: Patients referred for routine colonoscopy for colorectal cancer screening are asked to complete a validated questionnaire (modified GERQ) designed to determine the presence of symptomatic gastroesophageal reflux disease (GERD). Patients without established GERD or GERD symptoms are invited to participate in the trial. Enrolled patients undergo an EGD with standard technique including photographs of the gastroesophageal junction, and measurement of the lower esophageal sphincter (LES) location from the gums. Biopsies of the distal esophagus and any endoscopically abnormal tissue in the esophagus, stomach, or duodenum are obtained. A catheter-free pH-monitoring probe is then placed 6 cm above the LES and patients wear a recording monitor for 48 hours which they return, along with an activity diary, within 2–5 days. A total of 150 subjects are being recruited for this study. Results: To date, 31 asymptomatic individuals have been enrolled and undergone EGD. The mean age is 54.2 (26% female; 11% African-American). There have been 3 failed BRAVO capsule deployments and pH data is available on 91% of the subjects. 16/31 (52%) have tested positive for significant esophageal acid exposure defined by a Johnson-DeMeester (JD) score > 14.72 on either day 1 (13), day 2 (9), or both (6). Among these 16 asymptomatic patients, 4 (25%) had endoscopic (esophagitis) and/or histologic evidence of reflux changes. There were 3 asymptomatic patients who had evidence of acid reflux changes either endoscopically or histologically who had either a normal JD score or no JD score due to failed capsule deployment. Therefore, a total of 7/31 (22.6%) asymptomatic patients had evidence of significant esophageal acid exposure. In addition, the prevalence of esophagitis and Barrett's esophagus were 2/31 (6.5%) and 2/31 (6.5%) respectively. There are no statistically significant relationships identified thus far between acid exposure and BMI, sex, race, age, and ETOH/wk or coffee/day intake. Conclusions: Our interim analysis indicates that significant esophageal acid exposure is common in an asymptomatic population. Exposure is variable with endoscopic or histologic evidence of GERD and reassessment of our current reference standards for pHmetry may be warranted.