title: The extent of oesophageal acid exposure overlap among the different gastro-oesophageal reflux disease groups.
abstract: BACKGROUND
  Studies have demonstrated that patients with Barrett's oesophagus have the highest oesophageal acid exposure profile, followed by erosive oesophagitis and non-erosive reflux disease patients, but the exact extent of overlap remains unknown.
  
  
  OBJECTIVE
  To determine the extent of overlap in oesophageal acid exposure among the different gastro-oesophageal reflux disease groups.
  
  
  METHODS
  A total of 121 patients with gastro-oesophageal reflux disease underwent an upper endoscopy and were classified as having Barrett's oesophagus, erosive oesophagitis and non-erosive reflux disease-all (non-erosive reflux disease-positive and functional heartburn). Subsequently, patients underwent pH testing and overlap in oesophageal acid exposure among the different gastro-oesophageal reflux disease groups was determined.
  
  
  RESULTS
  Of those enrolled, 24 had Barrett's oesophagus, 30 erosive oesophagitis and 28 were non-erosive reflux disease-positive. Mean oesophageal acid exposure time was 224.8 +/- 35, 134.3 +/- 21.9 and 141.3 +/- 19.8 min for Barrett's oesophagus, erosive oesophagitis and non-erosive reflux disease-positive respectively. Per cent overlap for total, upright and supine time between non-erosive reflux disease-positive and erosive oesophagitis was 47.4%, 64.7% and 81.8%, between Barrett's oesophagus and erosive oesophagitis was 47.8%, 40.7% and 24%, and between Barrett's oesophagus and non-erosive reflux disease-positive was 31.6%, 37.5% and 20.8% respectively.
  
  
  CONCLUSIONS
  Our study demonstrated a high oesophageal acid exposure overlap between patients with non-erosive reflux disease-positive and erosive oesophagitis, Barrett's oesophagus and erosive oesophagitis, as well as Barrett's oesophagus and non-erosive reflux disease-positive patients.
authors.affiliation: The Neuro-Enteric Clinical Research Group, Section of Gastroenterology, Department of Medicine, Southern Arizona VA Health Care System and University of Arizona Health Sciences Center, Tucson, AZ 85723-0001, USA.
authors.forename: M
authors.initials: M
authors.lastname: Shapiro
authors.forename: C
authors.initials: C
authors.lastname: Green
authors.forename: E M
authors.initials: EM
authors.lastname: Faybush
authors.forename: R F
authors.initials: RF
authors.lastname: Esquivel
authors.forename: R
authors.initials: R
authors.lastname: Fass
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001471:Barrett Esophagus / Q000378:metabolism; D004942:Esophagitis, Peptic / Q000378:metabolism; D004945:Esophagoscopy / Q000379:methods; D004947:Esophagus / Q000293:injuries* / Q000378:metabolism; D005260:Female; D005744:Gastric Acid / Q000378:metabolism*; D005764:Gastroesophageal Reflux / Q000378:metabolism*; D006356:Heartburn / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008875:Middle Aged; D013997:Time Factors