Correlation of oesophageal acid exposure with Barrett's oesophagus length

Background - Gastro-oesophageal reflux disease (GORD) plays a major role in the development of Barrett's oesophagus. However, it has yet to be elucidated what factors determine the length of Barrett's mucosa in each individual patient. Aims - To determine if there is a correlation between oesophageal acid exposure and the length of Barrett's mucosa. We also compared the extent of oesophageal acid exposure between patients with short segment (SSBE) and long segment (LSBE) Barrett's oesophagus. Methods - Twenty seven patients with Barrett's oesophagus were recruited prospectively into the study from the outpatient gastroenterology clinic at the Southern Arizona VA Health Care System. Diagnosis of Barrett's oesophagus and its anatomical characteristics were determined during upper endoscopy. Ambulatory 24 hour oesophageal pH monitoring assessed the extent of oesophageal acid exposure. Results - There was a significant correlation between per cent total time pH less than 4 and length of Barrett's mucosa (r=0.6234, p=0.0005). In addition, there was a significant correlation between per cent upright and supine time pH less than 4 and length of Barrett's mucosa (r=0.5847, p=0.0014 and r=0.6265 p=0.0006, respectively). Patients with SSBE had significantly less oesophageal acid exposure than patients with LSBE, in terms of both per cent total time and per cent supine time pH less than 4 (p<0.05). Conclusions - The length of Barrett's mucosa correlated with the duration of oesophageal acid exposure. Patients with LSBE experienced significantly more oesophageal acid exposure than patients with SSBE. Duration of oesophageal acid exposure appears to be an important contributing factor in determining the length of Barrett's mucosa.