Esophageal pH and impedance reflux parameters in relation to body mass index, obesity related hormones and bariatric procedures

Introduction Obese patients have a higher risk of gastroesophageal reflux disease (GERD), but obesity‑related hormonal changes associated with GERD and the effects of bariatric therapy on reflux are unclear. Objectives The aim of the study was to assess reflux parameters in relation to bariatric therapy and hormonal changes in obese patients. Patients and methods This prospective observational study with a 1‑year follow‑up included 53 obese patients undergoing bariatric therapies. Esophageal pH and impedance monitoring tests were performed and circulating hormone levels were analyzed. Results Esophageal acid exposure time (%AET) and the number of refluxes correlated positively with body mass index. There were several significant, although weak, correlations of pH and impedance parameters with ghrelin and omentin levels. Patients with abnormal %AET had lower ghrelin levels and those with abnormal reflux number had lower omentin levels than patients with normal parameters. Although we observed certain changes including increased %AET and bolus clearance time (BCT) after laparoscopic sleeve gastrectomy, a reduced BCT and number of refluxes after gastric band, and nonsignificant changes after intragastric balloon, the overall bariatric therapy did not significantly impact on the final GERD diagnosis. GERD before and after therapy was present in 42% of patients. De novo GERD developed in 17.8% of patients, while a similar percentage of patients with initial GERD had normal pH and impedance after therapy. Patients with de novo or persistent GERD had a similar percentage of weight loss as patients without GERD. Conclusions Bariatric therapy and percentage of weight loss do not significantly affect GERD. The observed hormonal changes alone do not fully explain the high prevalence of GERD in obese patients.