Associations between Pouchitis and Fecal Calprotectin after Restorative Proctocolectomy in Patients with Ulcerative Colitis

INTRODUCTION: Recently, fecal calprotectin has been identified and used as an assessment tool for the confirmation of disease activity in ulcerative colitis. Although a meta-analysis suggested the usefulness of fecal calprotectin for the assessment of pouchitis, the number of participants was still insufficient. Therefore, we prospectively measured fecal calprotectin levels during pouchoscopy and analyzed their associations with pouchitis. METHODS: Patients who underwent pouchoscopy after total proctocolectomy and ileal pouch-anal anastomosis for ulcerative colitis were included. Fecal samples were collected for the measurement of calprotectin during pouchoscopy. Patients either with or without suspicious pouchitis were included. Pouchitis was defined as a modified pouchitis disease activity index (m-PDAI) score of ≥5. The associations between the development of pouchitis and the m-PDAI score and fecal calprotectin and serum markers, including C-related protein, albumin, and white blood cells, were assessed. RESULTS: A total of 170 patients were included. Seventy-two patients were diagnosed with pouchitis with an m-PDAI score of 7.3 ± 1.5. The values of fecal calprotectin were 1,500 ± 1,544 μg/g in patients with pouchitis and 259 ± 402 μg/g in patients without pouchitis (p < 0.01). The correlation coefficient between calprotectin and the m-PDAI score was significant (r(2) = 0.279, p < 0.001). The cutoff value of fecal calprotectin in receiver operating characteristic analysis was 246 μg/g (area under curve 0.85, sensitivity 83.9%, specificity 71.0%). Fecal samples were able to be collected from 6 patients. The levels of fecal calprotectin significantly decreased from 2,101.3 ± 880.3 μg/g to 284.2 ± 96.9 μg/g in response to the treatment. CONCLUSIONS: Elevated fecal calprotectin appeared to be significantly correlated with pouchitis. We should consider the alteration of this marker during treatments in further studies.