P489 Predicting mucosal state with faecal calprotectin in children with Crohn’s disease.
M. Meglicka*1, M. Szczepanski2, M. Dadalski2, J. Kierkus2
1The Children’s Memorial Health Institute, Department of Gastroenterology, Hepatology, Feeding Disorders and Paediatrics, Warsaw, Poland, 2The Children’s Memorial Health Institute, Department of Gastroenterology, Hepatology, Feeding Disorders and Paediatrics, Warsaw, Poland
Faecal calprotectin (FC) is a good marker in monitoring mucosal healing in adults with Crohn’s disease (CD). Its concentrations in faeces is related to state of mucosa observed in endoscopy. Only few studies in paediatric CD patients concern the role of FC in mucosa status assessment.
In total, 68 patients with CD (F 26, M 42, and ± 12.51 years) were involved to the study and had elective colonoscopy performed and FC level and haematocrit (HT) within a week before endoscopy measured. Each patient had also Paediatric Crohn’s Disease Activity Index (PCDAI) calculated. Mucosa status was assessed during endoscopy with Simple Endoscopic Score for Crohn’s Disease (SES-CD). Full mucosal healing was defined as SES-CD = 0. We have identified 2 sub-groups: patients with full mucosal healing, and patients with inflamed gut mucosa. The receiver-operating characteristic curve (ROC) was used as a statistical method to establish cut-off points. The cut-off points are FC level for simple model and probability threshold for the logistic regression. The area under the curve (AUC) assesses the differentiation quality of the study group based on the model score. To increase specificity at high sensitivity, the logistic regression with other predictors was made. The final model was selected using cross-validation.
AUC for the simple model was 0.86. The selected cut-off level of discrimination between the sub-group with full mucosal healing vs sub-group with mucosal inflammation was 59 μg/g with specificity 0.94 and sensitivity 0.56. When sensitivity was outweighed over specificity the cut-off point was 1442 μg/g, with specificity 0.36 and sensitivity 0.94. With logistic regression on FC, CRP, HT, and PCDAI, the AUC was 0.85, and we could discriminate our patient with specificity 0.50 and sensitivity 0.94.
FC is a good marker of mucosal healing in monitoring of children with CD. FC below 59 μg/g enable us to select 56% of patients with full mucosal healing. Logistic regression with FC, HT and PCDAI let us select 50% of patients with inflamed mucosa. Using these 2 methods, step by step, we could discriminate 44% of patients with unknown mucosa status that require endoscopy.