title: Reflux episodes detected by impedance in patients on and off esomeprazole: a randomised double-blinded placebo-controlled crossover study.
abstract: BACKGROUND
  Combined with 24-h pH monitoring, the use of impedance is the most sensitive method available for detecting oesophageal reflux. Normal values for impedance have been previously established in healthy controls studied on and off proton pump inhibitors (PPI).
  
  
  OBJECTIVE
  To determine the effects of PPIs on the total number of reflux episodes in the distal oesophagus measured by impedance in patients with and without gastro-oesophageal reflux disease (GERD).
  
  
  METHODS
  In this prospective randomised double-blinded placebo controlled crossover study, all patients underwent two 24-h pH with impedance studies at least 2 weeks apart. Based on a randomisation scheme, patients received either 40 mg of esomeprazole twice daily for 1 week or identical capsule placebo for 1 week, then all patients were crossed over to the other treatment arm. GERD was defined by the validated Johnson-DeMeester score. Reflux by impedance was defined as a 50% decrease from baseline in retrograde movement of liquid between two impedance sites.
  
  
  RESULTS
  Sixty-three patients were enrolled and 41 patients completed the study [mean age 52 ± 12 years, 42% (17/41) men, 56% (23/41) Caucasian and 34% (14/41) African American]. Overall, there was no significant decrease in the total number of distal impedance episodes with esomeprazole compared with placebo (mean change 6.1 ± 22, P = 0.100). When analysed separately by GERD status, among GERD-positive patients, there was a significant decrease in distal impedance episodes while on esomeprazole compared with placebo (mean change -16 ± 22, P = 0.023), but not in GERD-negative patients (mean change -0.35 ± 20, P = 0.872).
  
  
  CONCLUSIONS
  Esomeprazole decreases significantly the number of reflux episodes detected by impedance, but only in patients with GERD.
authors.affiliation: Department of Medicine, Gastroenterology Service, Walter Reed National Military Medical Center, Bethesda, MD 20889, USA. Fouad.Moawad@us.army.mil
authors.forename: F J
authors.initials: FJ
authors.lastname: Moawad
authors.forename: J D
authors.initials: JD
authors.lastname: Betteridge
authors.forename: J A
authors.initials: JA
authors.lastname: Boger
authors.forename: F-K F
authors.initials: FK
authors.lastname: Cheng
authors.forename: L S
authors.initials: LS
authors.lastname: Belle
authors.forename: Y-J
authors.initials: YJ
authors.lastname: Chen
authors.forename: C L
authors.initials: CL
authors.lastname: Maydonovitch
authors.forename: R K H
authors.initials: RK
authors.lastname: Wong
mesh_terms: D000328:Adult; D000897:Anti-Ulcer Agents / Q000627:therapeutic use*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D017097:Electric Impedance; D064098:Esomeprazole / Q000627:therapeutic use*; D050782:Esophageal pH Monitoring; D005260:Female; D005764:Gastroesophageal Reflux / Q000175:diagnosis / Q000188:drug therapy* / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D054328:Proton Pump Inhibitors / Q000627:therapeutic use; D016896:Treatment Outcome
chemical_list: D000897:Anti-Ulcer Agents; D054328:Proton Pump Inhibitors; D064098:Esomeprazole