Clinical utility of C-reactive protein in patients with ileal pouch anal anastomosis

Inflammatory and noninflammatory complications of ileal pouch-anal anastomosis (IPAA) are common after restorative proctocolectomy for ulcerative colitis (UC). The clinical utility of C-reactive protein (CRP) in ileal pouch disorders has not been investigated.

All IPAA patients with underlying UC who had serum CRP tested within 2 weeks of pouch endoscopy were included. The correlation between the level of serum CRP and the Pouch Disease Activity Index (PDAI) scores were evaluated. Diagnostic accuracy of CRP in assessing disease activity by PDAI endoscopy subscores was evaluated.

There were 83 patients (with a total 88 CRP tests), including normal pouches (n = 7), active pouchitis (n = 6), chronic pouchitis (n = 18), Crohn's disease of the pouch (n = 23), cuffitis (n = 13), irritable pouch syndrome (n = 10), and surgery-associated complications (n = 11). Levels of CRP did not differ significantly among healthy and diseased pouch groups. CRP levels significantly correlated with the PDAI endoscopy subscores in the pouch body (P = 0.006) and afferent limb (P = 0.03). A CRP level of greater than 0.7 mg/dL for CRP using the receiver operating characteristics curve obtained the best sensitivity of 69.7% and specificity of 63.6% to detect active pouch inflammation.

Serum CRP levels correlated with endoscopic inflammation in the pouch and afferent limb. Elevated CRP levels might be useful to monitor the degree of inflammatory activity in pouch noninvasively. However, the CRP level as a snapshot had a limited role in distinction between healthy and diseased pouch conditions diagnosed based on longitudinal clinical and endoscopic evaluation.