title: Acid and non-acid reflux patterns in patients with erosive esophagitis and non-erosive reflux disease (NERD): a study using intraluminal impedance monitoring.
abstract: BACKGROUND
  Non-erosive reflux disease (NERD) and erosive esophagitis (EE) are the most common phenotypic presentations of gastroesophageal reflux disease (GERD).
  
  
  OBJECTIVE
  To assess acid and non-acid reflux patterns in patients with EE and NERD using combined esophageal pH-impedance monitoring.
  
  
  METHODS
  A total of 26 GERD patients off acid-suppressive medication and ten healthy volunteers (HV) underwent upper endoscopy and 24-h pH-impedance monitoring. Analysis of the pH-impedance signals included total reflux time, number of reflux episodes according to gas-liquid composition, and pH (acid, non-acid).
  
  
  RESULTS
  EE was identified in 13 patients and NERD in 13 patients. Pathologic acid reflux was found in 92.3 and 69.2% of patients with EE and NERD, respectively (P = 0.15). When compared to HV, EE patients and NERD patients showed a higher incidence of acid (P = 0.002 and P < 0.001, EE vs. HV and NERD vs. HV, respectively) and non-acid reflux episodes (P = 0.03 and P = 0.001, EE vs. HV and NERD vs. HV, respectively). Mean reflux times, as assessed by both pH-metry and impedance monitoring, and incidence of acid and non-acid reflux episodes were similar in EE and NERD patients. In the supine position, however, EE patients showed a higher incidence of acid (P = 0.048) and liquid reflux episodes (P = 0.07).
  
  
  CONCLUSIONS
  Whereas EE patients have more acid reflux episodes in the supine position than NERD patients, patients with EE and NERD have similar non-acid reflux patterns. This observation lends support to the notion that non-acid reflux is less damaging to the esophageal mucosa than acid reflux.
authors.affiliation: Department of Gastroenterology and Hepatology, University Medical Center, P.O. Box 85500, 3508 GA Utrecht, The Netherlands. jconchillo@hotmail.com
authors.forename: José M
authors.initials: JM
authors.lastname: Conchillo
authors.forename: Matthijs P
authors.initials: MP
authors.lastname: Schwartz
authors.forename: Mohamed
authors.initials: M
authors.lastname: Selimah
authors.forename: Melvin
authors.initials: M
authors.lastname: Samsom
authors.forename: Daniel
authors.initials: D
authors.lastname: Sifrim
authors.forename: André J
authors.initials: AJ
authors.lastname: Smout
mesh_terms: D000328:Adult; D000368:Aged; D050782:Esophageal pH Monitoring / Q000295:instrumentation*; D004942:Esophagitis, Peptic / Q000503:physiopathology*; D004945:Esophagoscopy; D005260:Female; D005764:Gastroesophageal Reflux / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008365:Manometry; D008875:Middle Aged; D011187:Posture; D018709:Statistics, Nonparametric