The diagnostic accuracy of fecal calprotectin in pouchitis

Abstract

Introduction: Total proctocolectomy with ileal pouch-anal anastomosis (IPAA) represents the most common surgical procedure for intractable ulcerative colitis (UC), although up to 50% of the patients undergoing surgery will develop pouchitis. The diagnosis of pouchitis requires both pouch endoscopy and biopsy. Searching for non invasive markers which correlate with the degree of the mucosal inflammation is becoming more and more important. The aim of our prospective study was to compare fecal calprotectin in patients with and without pouchitis assessed by clinical, endoscopic and histological scores and to evaluate the diagnostic accuracy of fecal calprotectin in pouchitis. Patients and methods: Stool and blood samples were collected in 27 IPAA patients (female/male ratio: 16/11; mean age at UC diagnosis: 40.5 years; mean age at operation: 35.7 years, mean time since pouch formation: 50 months) before control endoscopy. Pouchoscopy was performed to evaluate the macroscopic inflammation of the pouch. Biopsies from the reservoir were taken for histology. Pouchitis was defined as Pouchitis Disease Activity Index (PDAI) > 4 points. The presence of cuffitis was evaluated by endoscopy. Calprotectin were quantified by use of enzyme-linked immunosorbent assay. Results: Pouchitis was detected in 30% of the patients. The median PDAI was 1.5. Cuffitis was presented in 8 cases. Fecal calprotectin was significantly higher in patients with vs. without pouchitis (560 vs. 82, p=0.01), but not with cuffitis. The cut-off value for fecal calprotectin in the diagnosis of pouchitis revealed to be 182µg/g with a sensitivity of 99.9% and a specificity of 69.2%. Discussion: Fecal calprotectin proved to be a reliable marker for the determination of pouch inflammation which may be helpful in the diagnosis of pouchitis and in the differentiation between pouchitis and cuffitis.