Reflux Episode Reaching the Proximal Esophagus Are Associated with Chronic Cough

BACKGROUND/AIMS: Gastroesophageal reflux (GER) has been implicated in the pathogenesis of chronic cough. The aims of this study were to evaluate the diagnostic usefulness of multichannel intraluminal impedance combined with pH monitoring (MII/pH monitoring) in patients with suspected symptoms of gastroesophageal reflux disease (GERD) and to assess the correlation between GER symptoms and reflux nature. METHODS: Seventy patients with suspected symptoms of GERD (such as heartburn, acid regurgitation, non-cardiac chest pain, globus and chronic cough) were enrolled. All patients were asked to discontinue medications that would influence esophageal motor function and gastric acid secretion at least one week ago. All subjects underwent MII/pH monitoring. RESULTS: Forty-five patients (64.3%) were diagnosed with GERD. Among these patients, eleven patients (15.7%) had pathologic acid reflux by pH data and thirty-four patients (48.6%) had pathologic bolus exposure by impedance. Subjects with chronic cough had a higher DeMeester score (p=0.009), percentage of acid exposure time (p=0.007), acid bolus exposure % time (p=0.027), distal acid reflux episodes (p=0.015) and proximal acid reflux episodes (p=0.030) than subjects without chronic cough. CONCLUSIONS: The results of this study showed that the impedance monitoring enhanced diagnostic sensitivity than pH-monitoring alone by 48.6%. In addition, reflux episodes at the distal and proximal esophagus were noted to be important factors associated with chronic cough.