title: Inter- and intra-observer variability of the Los Angeles classification: a reassessment.
abstract: BACKGROUND
  Los Angeles classification is widely adopted for reporting endoscopic gastroesophageal reflux disease. We assessed the inter- and intra-observer variability of the Los Angeles classification.
  
  
  METHODS
  Still images (n = 254) of the lower esophagus were presented to 9 gastroenterologists (6 experts and 3 trainees) and they were asked to report the images according to the Los Angeles classification. After 2 weeks the images were reordered and they were asked to report them again. Kappa statistic was calculated for intra- and inter-observer variability.
  
  
  RESULTS
  The kappa for intra-observer agreement was 0.54 (attendings: 0.54; trainees; 0.55; P = not significant) and the inter-observer agreement was 0.22 (attendings: 0.20; trainees: 0.31; P = 0.027). The inter- and intra-observer kappa values in differentiating nonerosive from erosive cases were 0.22 (attendings: 0.21; trainees: 0.31, P = not significant) and 0.57 (attendings: 0.58; trainees: 0.55, P = not significant), respectively.
  
  
  CONCLUSIONS
  According to our data, the Los Angeles classification has acceptable intra-observer variability, both for detecting presence or absence of erosions and for differentiating between different degrees of esophagitis, while its inter-observer performance seems to be less acceptable. It may be reasonable and timely to have another look at the Los Angeles classification to see whether its performance can be improved even further.
authors.affiliation: Digestive Disease Research Center (DDRC), Tehran University of Medical Sciences Tehran, Iran. sianm@ams.ac.ir.
authors.forename: Siavosh
authors.initials: S
authors.lastname: Nasseri-Moghaddam
authors.forename: Hadi
authors.initials: H
authors.lastname: Razjouyan
authors.forename: Mehdi
authors.initials: M
authors.lastname: Nouraei
authors.forename: Maysam
authors.initials: M
authors.lastname: Alimohammadi
authors.forename: Mansoureh
authors.initials: M
authors.lastname: Mamarabadi
authors.forename: Homayoon
authors.initials: H
authors.lastname: Vahedi
authors.forename: Akram
authors.initials: A
authors.lastname: Pourshams
authors.forename: Mehdi
authors.initials: M
authors.lastname: Mohamadnejad
authors.forename: Farhad
authors.initials: F
authors.lastname: Zamani
authors.forename: Farhad
authors.initials: F
authors.lastname: Sadr
authors.forename: Sodaif
authors.initials: S
authors.lastname: Darvish-Moghaddam
authors.forename: Pantea
authors.initials: P
authors.lastname: Farsi
authors.forename: Reza
authors.initials: R
authors.lastname: Malekzadeh
mesh_terms: D003937:Diagnosis, Differential; D016099:Endoscopy, Gastrointestinal / Q000706:statistics & numerical data*; D005764:Gastroesophageal Reflux / Q000145:classification* / Q000175:diagnosis; D006801:Humans; D015141:Los Angeles; D015588:Observer Variation