Construct Validity of the Toronto IBD Global Endoscopic Reporting Score Compared to Inflammatory Biomarkers after 12-Month Follow-Up

Background and Aims The Toronto IBD Global Endoscopic Reporting (TIGER) score is a single endoscopic scoring index for both patients with Crohn's disease (CD) and ulcerative colitis (UC). The goal of this study was to assess the direct relationship between TIGER scores and fecal calprotectin (FC) and C-reactive protein (CRP) after 12 months. Methods A prospective 12-month study conducted in 1 tertiary IBD center. Baseline colonoscopy was performed. Moderate-to-severe mucosal involvement was defined as a TIGER score ≥ 100, Simple Endoscopic Score for Crohn's disease ≥ 6, Mayo Endoscopic Score > 1. FC and CRP levels were documented at each visit. Baseline TIGER, SES-CD, and MES were utilized as a predictor for FC and CRP levels after 12 months. Results The study population included 107 adults, 52 with CD and 55 with UC. A baseline TIGER score ≥ 100 had a sensitivity and specificity of 0.964 and 0.941, respectively, at predicting a patient having an FC level ≥ 800 μg/g and/or a CRP level ≥ 1.0 mg/dL at 12-month follow-up. A baseline TIGER score ≥ 100 was associated with increased likelihood of having FC > 100 μg/g (P < .001), and ≥ 800 μg/g (P < .001) after 12 months, despite receiving advanced therapy, after the 12-month follow-up period. Similar trends were observed with the SES-CD and MES. Conclusions The TIGER score is a simple endoscopic score that can be used for both CD and UC that has been shown to have both construct validity with inflammatory marker and noninferiority to the current best-referenced endoscopic scores over a 12-month follow-up period. Future studies should begin incorporating TIGER as a measure of clinical response to interventions and therapeutics.