Development and validation of an endoscopic activity score for canine inflammatory bowel disease

- The endoscopic activity score correlates with the endoscopist's assessment of abnormal mucosal appearance.
- Mucosal assessment is consistent when evaluated in patients different than that used for score development.
- The activity score incorporates mucosal variables intuitively considered as important by experienced endoscopists.
- The activity score incorporates mucosal variables previously shown to be reproducibly collected, and is itself reproducible.
- The activity score is simple to calculate.

The aim of this study was to develop and prospectively validate a simple endoscopic score of disease activity for dogs with inflammatory bowel disease (IBD). Archived endoscopic still images and video recordings of gastric, duodenal, and colonic endoscopic examinations were displayed to novice and experienced endoscopists for assessment of inflammatory activity using established descriptions. The mucosal appearances evaluated were normal tissue, erosions, friability, increased granularity, lymphangiectasia (duodenum), and mass (colon). Fleiss and Cohen's Kappa statistics were used to estimate the inter-observer agreement of the index.For duodenal assessment, there were statistically significant (P <0.05) differences in inter-observer agreement, with experienced endoscopists performing better than novice endoscopists in the accurate identification of mucosal appearance of the duodenum. In contrast, there was no significant difference between novice and experienced endoscopists in their interpretation of gastric (P = 0.10) and colonic (P = 1.0) mucosal appearances. Validation studies using endoscopic video clips to assess the same endoscopic parameters by quantitative (lesion number and severity) and qualitative (presence of mucosal lesions) methods showed moderate-to-substantial agreement between experienced endoscopists. Based on the observations that the quantitative and qualitative scores of mucosal appearances are virtually identical, and that qualitative assessment was performed more quickly and objectively than quantitative assessment, we propose a simple endoscopic activity score based on qualitative criteria alone in dogs with inflammatory bowel disease.