A prospective study of gastric acid analysis and esophageal acid exposure in patients with gastroesophageal reflux refractory to medical therapy.

A number of factors have been proposed to account for the lack of response to medical therapy in patients with gastroesophageal reflux; however, no controlled studies are available in the literature. The goal of this study was to determine possible causes of medical refractoriness in patients with gastroesophageal reflux. Gastric acid output and esophageal acid exposure were measured in patients who continue to have reflux symptoms despite aggressive antisecretory therapy. In addition, an upper endoscopy was also performed in each patient. Patients with a drug-controlled acid output < 1 mEq/hr and a supine total esophageal pH < 4 for less than 1.7% of the time measured were considered responsive to therapy; on the other hand, those with a drug-controlled gastric acid output > 1 mEq/hr and a supine esophageal pH < 4 for more than 1.7% of the time measured were considered resistant to therapy. Twenty-four patients met the inclusion criteria (13 male and 11 female; mean age, 52). Drug-controlled gastric acid output was more than 1 mEq/hr in 25% of patients and less than 1 mEq/hr in the remainder. Of those patients with a gastric acid output of less than 1 mEq/hr (18 patients), 8(44%) had a supine esophageal pH < 4 for more than 1.7% of the time, suggesting that factors other than gastroesophageal reflux likely contributed to their reflux-like symptoms. Acid suppression appears adequate in the majority of patients with gastroesophageal reflux refractory to medical therapy. The exact cause of persistent reflux-like symptoms in patients who fail medical treatment is uncertain but may be related to non-acid-related factors such as esophageal hypersensitivity to physiologic reflux, increased intake of air resulting in aerophagia, or other factors such as bile reflux.