The Toronto IBD Global Endoscopic Reporting [TIGER] Score: A Single, Easy to Use Endoscopic Score for Both Crohn's Disease and Ulcerative Colitis Patients

Background and Aims: We constructed the Toronto IBD Global Endoscopic Reporting [TIGER] score for inflammatory bowel disease [IBD]. The aim of our study was to develop and validate the TIGER score against faecal calprotectin [FC], C-reactive protein [CRP], and IBD Disk. Methods: A cross-sectional study was performed among 113 adult patients (60 Crohn's disease [CD] and 53 ulcerative colitis [UC]). In the development and usability phase, blinded IBD experts reviewed and graded ileocolonoscopy videos. In the validity phase the TIGER score was compared with: [1] the Simple endoscopic Score for CD [SES-CD] and the Mayo endoscopic score in CD and UC, respectively; [2] FC and CRP; and [3] IBD Disk. Results: Inter-observer reliability of the TIGER score per segment between reviewers was excellent: interclass correlation coefficient [ICC] = 0.94 [95% CI: 0.92-0.96]. For CD patients, overall agreement per segment between SES-CD and TIGER was 91% [95% CI: 84-95] with kappa coefficient 0.77 [95% CI: 0.63-0.91]. There was a significant correlation between TIGER and CRP [p <0.0083], and TIGER and FC [p <0.0001]. In addition, there was significant correlation between TIGER and IBD Disk [p <0.0001]. For UC patients, overall agreement per segment between Mayo endoscopic score and TIGER was 84% [95% CI: 74%-90%] and kappa coefficient 0.60 [95% CI: 0.42-0.808]. There was a significant correlation between TIGER and FC [p <0.0001]. There was a significant correlation between TIGER and IBD Disk [p <0.0001]. Conclusions: The TIGER score is a reliable and simple novel endoscopic score that can be used for both CD and UC patients and captures full endoscopic disease burden.