- OBJECTIVES: The objective of this study was to compare the degree of esophageal acid exposure and duodenogastroesophageal reflux (DGER) during treatment between gastroesophageal reflux disease (GERD) patients who responded fully to proton pump inhibitor (PPI) once a day and those who failed to respond. METHODS: Gastroesophageal reflux disease patients who continued to report symptoms 3 times a week for 3 months while on PPI once a day were assigned to the PPI failure group. GERD patients who were asymptomatic on PPI once a day for 3 months were assigned to the PPI success group. All patients underwent upper endoscopy to assess esophageal mucosal injury. Subsequently, all patients underwent simultaneous 24-h esophageal Bilitec 2000 and pH testing while on treatment. Patients recorded GERD-related symptoms during the test. RESULTS: Twenty-four patients were enrolled in the PPI failure group and 23 patients were enrolled in the PPI success group. Endoscopy was normal in 63% of PPI failure patients and 76% of PPI success patients. Abnormal DGER was documented in 82% of PPI success patients vs. 67% of PPI failure patients (P=NS). All pH testing and Bilitec parameters in the PPI failure group were similar to those in the PPI success group (P=NS). Of the 34 GERD symptoms recorded by the PPI failure group, 64% were associated with acid reflux and 41% were associated with DGER (P<0.05). CONCLUSIONS: There is no difference in the degree of DGER and acid exposure during treatment between patients who failed to respond and those who achieved complete symptom resolution on PPI once daily. GERD symptoms in the PPI failure group are more commonly associated with acid reflux than with DGER.