Reflux pattern and role of impedance-pH variables in predicting PPI response in patients with suspected GERD-related chronic cough

Aliment Pharmacol Ther. 2014 Oct;40(8):966-73. doi: 10.1111/apt.12919. Epub 2014 Aug 11.


Background: Gastro-oesophageal reflux disease (GERD) may contribute to the onset of chronic cough (CC); however, the multichannel intraluminal impedance-pH (MII-pH) monitoring is often within the normal range and the response to proton pump inhibitors (PPIs) unsatisfactory. The measure of impedance baseline (IB) increases the sensitivity of MII-pH in patients with typical symptoms.

Aim: To evaluate the role of MII-pH variables, including IB, in predicting PPI response and to define the characteristics of the reflux pattern in CC patients.

Methods: Prospectively selected CC patients suspected GERD-related underwent MII-pH monitoring and, therefore, received a double dose of PPIs for at least 6 weeks. Patients filled symptom scores before MII-pH and after PPI therapy. MII-pH data were compared with those obtained in 60 non-erosive reflux disease patients with typical symptoms.

Results: A total of 156 CC patients entered the study: 68 (43.5%) responders and 88 (56.5%) nonresponders to PPIs. The number of reflux episodes was significantly higher in CC compared with that in typical symptoms patients. Nonresponder CC patients with a pathological acid exposure time (AET) and/or IB value were 43/88 (49%), while 15/88 (17%) presented only pathological AET (P < 0.001). CC patients with a pathological AET or IB, or with both a pathological AET and IB, showed a probability of PPI response twofold greater than patients with normal AET and IB.

Conclusions: The presence of a pathological AET or pathological IB in CC patients is associated with a greater probability of PPI response. IB is a promising variable in patients with CC, as it increases the diagnostic yield of MII-pH and allows confirmation of the GERD diagnosis in these patients.

Publication types

  • Controlled Clinical Trial

MeSH terms

  • Adult
  • Aged
  • Chronic Disease
  • Cough / diagnosis*
  • Cough / drug therapy
  • Cough / etiology
  • Electric Impedance
  • Esophageal pH Monitoring
  • Female
  • Gastroesophageal Reflux / complications
  • Gastroesophageal Reflux / diagnosis*
  • Gastroesophageal Reflux / drug therapy
  • Humans
  • Hydrogen-Ion Concentration
  • Male
  • Middle Aged
  • Proton Pump Inhibitors / pharmacology
  • Proton Pump Inhibitors / therapeutic use*
  • Young Adult


  • Proton Pump Inhibitors