Endoscopic assessment of the oesophageal features of eosinophilic oesophagitis: Validation of a novel classification and grading system

Objective: Abnormalities are commonly identified during endoscopy in eosinophilic oesophagitis (EoE). There is no standardised classification to describe these features. This study aimed to evaluate the interobserver agreement of a grading system for the oesophageal features of EoE. Method: The proposed system incorporated the grading of four major oesophageal features (rings, furrows, exudates, oedema) and the presence of additional features of narrow calibre oesophagus, feline oesophagus, stricture and crepe paper oesophagus. Endoscopic videos from 25 patients with EoE and controls were reviewed by 21 gastroenterologists. Interobserver agreement was assessed by estimating multi-rater κ and the proportion of pairwise agreement. Results: Using the original grading system, agreement for rings, furrows and exudates was moderate (κ=0.38-0.46, 56-65% agreement) but poor for oedema (κ=0.23, 51% agreement). Identification of narrow calibre oesophagus had fair agreement (κ=0.30, 74% agreement) while feline oesophagus had poor agreement (κ=0.15, 68% agreement). After collapsing the severity grading for oedema and furrows and eliminating poorly performing features of feline oesophagus and narrow calibre oesophagus, a modified grading system demonstrated good agreement for the four major features of EoE (κ=0.40-0.54, 71-81% agreement) and additional features of stricture and crepe paper oesophagus (κ=0.52 and 0.58, 79% and 92% agreement). Conclusions: The proposed system for endoscopicallyidentified oesophageal features of EoE defines common nomenclature and severity scores for the assessment of EoE disease activity. The system has good interobserver agreement among practising and academic gastroenterologists.