title: Association between baseline impedance values and response proton pump inhibitors in patients with heartburn.
abstract: OBJECTIVE
  Esophageal impedance measurements have been proposed to indicate the status of the esophageal mucosa, and might be used to study the roles of the impaired mucosal integrity and increased acid sensitivity in patients with heartburn. We compared baseline impedance levels among patients with heartburn who did and did not respond to proton pump inhibitor (PPI) therapy, along with the pathophysiological characteristics of functional heartburn (FH).
  
  
  METHODS
  In a case-control study, we collected data from January to December 2013 on patients with heartburn and normal findings from endoscopy who were not receiving PPI therapy and underwent impedance pH testing at hospitals in Italy. Patients with negative test results were placed on an 8-week course of PPI therapy (84 patients received esomeprazole and 36 patients received pantoprazole). Patients with more than 50% symptom improvement were classified as FH/PPI responders and patients with less than 50% symptom improvement were classified as FH/PPI nonresponders. Patients with hypersensitive esophagus and healthy volunteers served as controls. In all patients and controls, we measured acid exposure time, number of reflux events, baseline impedance, and swallow-induced peristaltic wave indices.
  
  
  RESULTS
  FH/PPI responders had higher acid exposure times, numbers of reflux events, and acid refluxes compared with FH/PPI nonresponders (P < .05). Patients with hypersensitive esophagus had mean acid exposure times and numbers of reflux events similar to those of FH/PPI responders. Baseline impedance levels were lower in FH/PPI responders and patients with hypersensitive esophagus, compared with FH/PPI nonresponders and healthy volunteers (P < .001). Swallow-induced peristaltic wave indices were similar between FH/PPI responders and patients with hypersensitive esophagus.
  
  
  CONCLUSIONS
  Patients with FH who respond to PPI therapy have impedance pH features similar to those of patients with hypersensitive esophagus. Baseline impedance measurements might allow for identification of patients who respond to PPIs but would be classified as having FH based on conventional impedance-pH measurements.
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, University of Pisa, Pisa, Italy. Electronic address: nick.debortoli@gmail.com.
authors.forename: Nicola
authors.initials: N
authors.lastname: de Bortoli
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, University of Pisa, Pisa, Italy.
authors.forename: Irene
authors.initials: I
authors.lastname: Martinucci
authors.affiliation: Division of Gastroenterology, Department of Surgery, Oncology and Gastroenterology, University of Padua, Padua, Italy.
authors.forename: Edoardo
authors.initials: E
authors.lastname: Savarino
authors.affiliation: Gastroenterology Unit, Hospital of Bern, Switzerland.
authors.forename: Radu
authors.initials: R
authors.lastname: Tutuian
authors.affiliation: Gastroenterology Unit, Hospital of Modena, Italy.
authors.forename: Marzio
authors.initials: M
authors.lastname: Frazzoni
authors.affiliation: Obesity Research Center, Endocrinology Unit, University of Pisa, Pisa, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Piaggi
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, University of Pisa, Pisa, Italy.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Bertani
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, University of Genoa, Genoa, Italy.
authors.forename: Manuele
authors.initials: M
authors.lastname: Furnari
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, University of Pisa, Pisa, Italy.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Franchi
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, University of Pisa, Pisa, Italy.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Russo
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, University of Pisa, Pisa, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Bellini
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, University of Genoa, Genoa, Italy.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Savarino
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, University of Pisa, Pisa, Italy.
authors.forename: Santino
authors.initials: S
authors.lastname: Marchi
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D017097:Electric Impedance; D004935:Esophageal Diseases / Q000188:drug therapy* / Q000473:pathology*; D050782:Esophageal pH Monitoring; D005260:Female; D006356:Heartburn / Q000188:drug therapy* / Q000473:pathology*; D006801:Humans; D007558:Italy; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D054328:Proton Pump Inhibitors / Q000627:therapeutic use*; D016896:Treatment Outcome
chemical_list: D054328:Proton Pump Inhibitors
keywords: Functional GI Disorder; GERD; pH Monitoring; pH-Impedance Monitoring