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Continuous 48-hr Esophageal pH-metry in Obese Patients with Gastroesophageal Reflux Symptoms Compared to Non-Obese Patients

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Crowell, Michael D., Ph.D.; Decker, Anton G., M.D.; Schettler, V. Ann, B.S.N; Moirano, Michele M., P.A-C.; Kim, H. Jae, M.D.; Sharma, Virender K., M.D.

American Journal of Gastroenterology: September 2005 - Volume 100 - Issue - p S35
Supplement Abstracts Submitted for the 70th Annual Scientific Meeting of the American College of Gastroenterology: ESOPHAGUS
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Gastroenterology, Mayo Clinic College of Medicine, Scottsdale, AZ.

Purpose: Obesity is a risk factor for GERD symptoms and esophageal erosions, however data from 24-hour, catheter-based pH studies have been inconsistent. Patient discomfort and interference with normal diet and activities may limit catheter-based testing systems. The recently developed BRAVO® wireless pH-metry system is designed to reduce these limitations and to provide prolonged, continuous recording of esophageal pH for up to 48 hours.

Aim: We compared 48-hr esophageal pH-metry in obese (OB) and non-obse (NO) patients referred for complaints of heartburn.

Methods: 87 patients with GERD symptoms were studied over a continuous 48h period. Patients were separated into 2 groups by weight (NO < 30 kg/m2; n = 64; or OB ≥ 30 kg/m2; n = 23). The pH telemetry capsule was positioned transorally 6 cm above the squamocolumnar junction using endoscopic measurement or 5 cm above the upper margin of the LES using manometric measurements. Patients maintained a diary of activities throughout the study period. Data between groups and days were evaluated using Two-Way, Repeated Measures ANOVA controlling for PPI usage.

Results: OB and NO groups did not differ in age or gender (57 ± 17 yrs; 58% F vs 58 ± 14 yrs; 52% F). BMI was significantly greater in OB compared to NO patients (34.2 ± 3.8 vs 25.0 ± 2.8 kg/m2). No group differences were seen in acid exposure on Day 1 (% pH < 4.0 = 4.4 ± 0.63 vs 3.5 ± 1.8), but acid exposure was significantly elevated in the OB group (% pH < 4.0 = 8.02 ± 1.5) compared to NO (% pH < 4.0 = 4.1±1.1) on Day 2. Acid exposure was highest in both groups during the awake, upright periods (p < 0.05). The DeMeester score for Day 2 was also significantly higher in the OB group (28.7 ± 41.0) compared to the NO group (12.0 ± 16.8). Patterns of variability differed between groups. OB patients showed increased percent time pH < 4.0 from the 1st to the 2nd 24 h period, whereas NO patients showed a decrease.

Conclusions: Gastroesophageal acid reflux was greater in obese patients with GERD symptoms compared to non-obese patients. These differences were primarily noted during the second 24h recording and may be due to altered daily activities. Increased variability in esophageal acid exposure in obese patients supports the use of more prolonged pH studies in subsets of GERD patients.

© The American College of Gastroenterology 2005. All Rights Reserved.