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.