A validated risk stratification tool for detecting high‐risk small bowel Crohn's disease

Summary Background Delays in Crohn's disease (CD) diagnosis are positively associated with ileal location and an increased risk of complications. Aim To develop a simple risk assessment tool to enable primary care physicians to recognise potential ileal CD earlier, shortening the delay to specialist investigation Methods Three cohorts were acquired for this study. Cohort 1 included 61 patients retrospectively identified with ileal CD between 2000 and 2010 and 78 matched controls drawn from a cohort referred for investigation of abdominal symptoms. Cohort 2 included 42 individuals diagnosed with ileal CD and 57 controls identified prospectively. Cohort 3 included an additional 84 individuals with ileal CD and 495 without CD referred for colonoscopy. Clinical symptoms and serological biomarkers were acquired and used to develop a risk prediction algorithm. The algorithm was trained independently on each of the three cohorts and tested on the latter two cohorts. Results Altered bowel habit with abdominal pain combined with derangements in white cell count (WCC), albumin and platelet counts were important features in predicting ileal CD (AUC = 0.92, 95% CI = 0.89‐0.92). This was validated in cohorts 2 (AUC = 0.96, 95% CI = 0.95‐0.98) and 3 (AUC = 0.94, 95% CI = 0.92‐0.96). C‐reactive protein was independently associated with ileal CD but non‐signficant in a multivariate model. Conclusion A web‐based risk stratification tool for ileal CD has been developed from objective and symptom‐based criteria. This tool enables primary care physicians to more confidently request urgent specialist assessment for patients identified as at high risk for ileal CD.