title: The Montreal definition and classification of gastroesophageal reflux disease: a global evidence-based consensus.
abstract: OBJECTIVE
  A globally acceptable definition and classification of gastroesophageal reflux disease (GERD) is desirable for research and clinical practice. The aim of this initiative was to develop a consensus definition and classification that would be useful for patients, physicians, and regulatory agencies.
  
  
  METHODS
  A modified Delphi process was employed to reach consensus using repeated iterative voting. A series of statements was developed by a working group of five experts after a systematic review of the literature in three databases (Embase, Cochrane trials register, Medline). Over a period of 2 yr, the statements were developed, modified, and approved through four rounds of voting. The voting group consisted of 44 experts from 18 countries. The final vote was conducted on a 6-point scale and consensus was defined a priori as agreement by two-thirds of the participants.
  
  
  RESULTS
  The level of agreement strengthened throughout the process with two-thirds of the participants agreeing with 86%, 88%, 94%, and 100% of statements at each vote, respectively. At the final vote, 94% of the final 51 statements were approved by 90% of the Consensus Group, and 90% of statements were accepted with strong agreement or minor reservation. GERD was defined as a condition that develops when the reflux of stomach contents causes troublesome symptoms and/or complications. The disease was subclassified into esophageal and extraesophageal syndromes. Novel aspects of the new definition include a patient-centered approach that is independent of endoscopic findings, subclassification of the disease into discrete syndromes, and the recognition of laryngitis, cough, asthma, and dental erosions as possible GERD syndromes. It also proposes a new definition for suspected and proven Barrett's esophagus.
  
  
  CONCLUSIONS
  Evidence-based global consensus definitions are possible despite differences in terminology and language, prevalence, and manifestations of the disease in different countries. A global consensus definition for GERD may simplify disease management, allow collaborative research, and make studies more generalizable, assisting patients, physicians, and regulatory agencies.
authors.affiliation: University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53233, USA.
authors.forename: Nimish
authors.initials: N
authors.lastname: Vakil
authors.forename: Sander V
authors.initials: SV
authors.lastname: van Zanten
authors.forename: Peter
authors.initials: P
authors.lastname: Kahrilas
authors.forename: John
authors.initials: J
authors.lastname: Dent
authors.forename: Roger
authors.initials: R
authors.lastname: Jones
mesh_terms: D003697:Delphi Technique; D019317:Evidence-Based Medicine; D005764:Gastroesophageal Reflux / Q000145:classification*; D006801:Humans