Fecal Calprotectin Is Increased in Pouchitis and Progressively Increases With More Severe Endoscopic and Histologic Disease

Background & Aims: Data regarding fecal calprotectin (FC), commonly used for noninvasive monitoring in inflammatory bowel diseases, are scarce in patients with ileal pouch–anal anastomosis (IPAA). We aimed to assess the association between FC levels and pouch inflammation in patients with ulcerative colitis who underwent IPAA. Methods: A cross-sectional study of adults with ulcerative colitis who underwent IPAA with J-pouch formation prospectively followed in a dedicated pouch clinic. Patients had clinical, endoscopic, and histologic assessments within 90 days of FC sampling. Each patient encounter was evaluated separately. Pouchitis was defined as a Pouchitis Disease Activity Score of ≥7 (maximum score: 18). Results: Overall, 156 patients had 296 encounters that met inclusion criteria. A total of 52% of patients were male, median age at evaluation was 43 (IQR, 35–58) years, and median pouch age was 10 (interquartile range [IQR], 2.5–15) years. Median FC values were significantly lower in patients without compared with those with pouchitis (208 [IQR, 96–478] μg/g vs 550 [IQR, 250–1051] μg/g; P < .0001). Mean FC values increased among patients with higher endoscopic and histologic scores. FC performed better than C-reactive protein as a predictor of pouchitis. FC of >460 μg/g had >80% specificity for predicting significant endoscopic disease (Pouchitis Disease Activity Score endoscopic subscore ≥5), while an FC of <125 μg/g had over 80% specificity in predicting endoscopic remission. Conclusions: FC levels are increased in patients with endoscopic and histologic inflammation of the pouch. FC may be a useful tool in the management of patients following IPAA.