Relationship between rate of change in acid exposure along the esophagus and length of Barrett's epithelium.

Objective: Gastroesophageal reflux disease (GERD) plays a major role in the development of Barrett's esophagus. Recently, we demonstrated that duration of esophageal acid exposure in the distal esophagus correlates with the length of Barrett's mucosa. The aim of this study was to determine whether there is a relationship between the rate of the change in acid exposure along the esophagus and the length of Barrett's esophagus.

Methods: A total of 17 patients (16 men and one woman; mean age 66 +/- 15 yr, range 41-83 yr) with varying lengths of biopsy-proven Barrett's esophagus were recruited prospectively into the study. Ambulatory 24-h esophageal pH monitoring was performed using a commercially available pH probe with four sensors located 5 cm apart. For each patient, a least squares regression line of the fraction of the study that the pH was <4 against the height of the sensor above the lower esophageal sphincter was fit. The slope of the regression line was used to represent the rate of change in acid exposure. Linear regression analysis was conducted to analyze the relationship between the rate of change in acid exposure and the length of Barrett's mucosa.

Results: The mean Barrett's length was 5 +/- 3 cm (range 1-11 cm). Linear regression demonstrated a statistically significant relationship between the rate of change in acid exposure and the length of Barrett's esophagus for the 24-h duration of the study, as well as for the fraction of the study that patients were in the upright position (p = 0.0096 and 0.0076, respectively). For the supine position, the relationship did not reach statistical significance (p = 0.095).

Conclusions: We demonstrated a significant relationship between the rate of change in acid exposure and the length of Barrett's mucosa. Thus, as the rate at which recorded acid exposure values increases from the proximal to distal esophagus, the length of Barrett's esophagus significantly increases (for percent total time and upright position).