24-h pH-metry and multichannel intraluminal impedance monitoring in obese patients with and without gastroesophageal reflux disease symptoms.

BACKGROUND: The 24-h ambulatory pH-metry with multichannel intraluminal impedance monitoring (24-h pH-metry+MII) allows the simultaneous assessment of chemical and physical properties of esophageal refluxes and the detection of its proximal migration.
METHODS: Gastroesophageal reflux (GER) was investigated in obese symptomatic (obese gastroesophageal reflux disease, GERD) and asymptomatic (obese non-GERD) patients. The data were compared with those obtained from non-obese GERD patients and a control group. Thirty-five (20 non-GERD, 15 GERD) obese patients and 15 non-obese GERD were investigated with 24-h pH-metry+MII. Ten normal weight subjects with normal 24-h pH-metry+MII were used as control group.
RESULTS: The percent time acid exposure was significantly higher in obese non-GERD than controls (p = 0.007). Acid reflux episodes were increased vs. controls in obese non-GERD (p = 0.005) and obese GERD (p = 0.034). Upright position showed a significant increase of reflux episodes in non-obese GERD (p = 0.034) and in obese non-GERD (p = 0.027) vs. controls. Recumbent position showed reflux episodes significantly increased vs. controls in obese non-GERD (p = 0.002), obese GERD (p = 0.021), and non-obese GERD (p = 0.033). In obese non-GERD, waist circumference (WC) correlated negatively with upright position episodes (r = -0.53; p = 0.043) and with proximal migration episodes, i.e., total (r = -0.60; p = 0.018), acid (r = -0.55; p = 0.033), and weakly acidic refluxes (r = -0.56; p = 0.031).
CONCLUSIONS: Obese patients showed an increased number of refluxes with acid content. Refluxes with proximal extent were significantly higher in obese non-GERD than in controls and non-obese GERD patients. No difference was observed between the two obese patient groups. In asymptomatic obese patients, the WC correlated with proximal extent episodes.