Do preoperative factors predict subsequent diagnosis of Crohn's disease after ileal pouch-anal anastomosis for ulcerative or indeterminate colitis?

The aim of this study was to determine preoperative clinical factors associated with subsequent diagnosis revision to Crohn's disease (CD) following total proctocolectomy with ileal pouch-anal anastomosis (IPAA) for ulcerative colitis (UC) or indeterminate colitis (IC) patients. Presumed UC and IC patients undergoing IPAA from a large single-institution prospective database with change of diagnosis to CD were identified and compared with patients without diagnosis change. A total of 2814 patients (47% male, median age 37 years) with presumed UC (85%) or IC (15%) underwent primary IPAA. At a median follow up of 9.6 years, 184 (7%) had the diagnosis revised to CD from histopathological examination of the colectomy specimen immediately in 97 (53%) or at a median interval of 36 months in 87 (47%). CD and UC/IC patients had had a similar operative technique, length of stay and 30-day morbidity. The postoperative CD diagnosis was associated with a preoperative diagnosis of IC (P < 0.0001) and perianal fistula (P = 0.002). Patients with a delayed diagnosis of CD were associated with a 3-stage procedure (P < 0.0001, OR = 2.8) (95% CI = 1.8-4.4), colonic stricture (P = 0.04, OR = 2.9 [95% CI = 1.1-7.4]), perianal fistula (P = 0.02, OR = 2.9 [95% CI = 1.2-7.2]), oral ulceration (P = 0.009, OR = 3.8 [95% CI = 1.2-9.6]) and younger age (P < 0.0001, OR = 0.048 [95% CI = 0.011-0.19]). A few patients having IPAA for presumed UC/IC were subsequently diagnosed to have CD which was associated with perianal fistula and the diagnosis of postoperative preoperative IC. The delayed diagnosis of CD was associated with a three-stage procedure, colorectal stricture, anal fissure, mouth ulceration and younger age.