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

Aim 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. Method 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. Results 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