Faecal Calprotectin from Ileostomy Output Is Sensitive and Specific for the Prediction of Small Bowel Inflammation in Patients with Crohn's Disease.

Abstract

Severe Crohn's disease [CD] can result in extensive bowel resections and need for creation of an ileostomy. Faecal calprotectin [FC] is well studied in CD management, though its role in patients who have an ileostomy is unclear. Our aim is to understand if FC is a useful adjunct to radiographic or endoscopic studies in identifying recurrent CD after surgery in patients with an ileostomy. Between January 1, 2017, and September 30, 2020, we searched the Mayo Clinic electronic medical record retrospectively for adult patients with ICD-10 code for CD, and a surgical history of an ileostomy. Patients were included in the analysis if they had at least one FC measured and a concomitant radiographic imaging and/or endoscopic procedure. An abnormal FC was defined as greater than 60 µg/g. Of 51 patients who met our inclusion criteria, 17 had an FC level >60 µg/g. Of these 17 patients, 14 had imaging and/or an ileoscopy confirming the presence of small bowel inflammation, with a sensitivity of 87.5%. Of the remaining 34 patients with an FC level ≤60 µg/g, 32 patients had imaging and/or ileoscopy demonstrating no small bowel inflammation, with a specificity of 91.4%. FC from an ileostomy effluent had a positive predictive value of 82.3%, a negative predictive value of 94.1% and test diagnostic accuracy of 90.1%. FC from an ileostomy effluent is a highly sensitive and specific test for the assessment and monitoring of small bowel inflammation and disease recurrence in patients with CD.