P0302 Outcomes of Colectomy-IPAA for UC, Is De Novo-CD on the Rise?

Abstract

Abstract Background Restorative proctocolectomy with ileal pouch-anal anastomosis (IPAA) is the preferred surgical option for refractory ulcerative colitis (UC), dysplasia, or malignancy. De novo Crohn’s Disease (CD) is a recognized postoperative complication that can occur in UC patients after IPAA. Pouchitis, a common complication marked by nonspecific pouch inflammation, typically responds to antibiotics but can progress to proximal or penetrating transmural inflammation, later defined as de novo-CD. Methods This retrospective study analyzed UC patients who underwent proctocolectomy-IPAA between 2000 and 2022, focusing on the frequency of pouchitis and de novo-CD and associated risk factors. Results Among 1197 UC patients, 82 (6.8%) underwent proctocolectomy-IPAA. Of these, 65.9% (n=54) were male, with a mean UC diagnosis age of 35±12 years and a median disease duration of 49 (IQR: 112) months before surgery. Median follow-up was 83 (IQR: 86.5) months. Chronic inflammation was the primary indication for surgery, while malignancy accounted for 15.9%. Anti-TNF therapy was used in 37.8% of patients before colectomy, with a median duration of 9 (IQR: 9) months. De novo-CD developed in 32.9% of patients, with 48% presenting with fistulizing disease. The median time to de novo-CD diagnosis was 35 (IQR: 63) months, with fistulizing disease diagnosed slightly earlier at 31 (IQR: 52) months. One-third of de novo-CD cases were initially misdiagnosed as pouchitis. Pouchitis occurred in 52% (n=43) of patients, with a median onset of 18 (IQR: 27) months. Overall, 62% of patients required treatment for pouchitis or de novo-CD, with antibiotics being the most common therapy (52%, median 2 courses). Biological therapies, primarily used in de novo-CD cases, were utilized in 24% of patients. Patients with isolated pouchitis showed no significant differences in age at diagnosis, disease duration, gender, colectomy indication, or prior UC treatments compared to those without pouchitis. Pouchitis was more frequent in left-sided UC and less common in pancolitis. Emergency colectomy was associated with higher pouchitis rates. De novo-CD was more common in patients undergoing colectomy for malignancy and in surgeries performed in last decade. Conclusion De novo-CD develops in ~33% of UC patients after IPAA, typically within 2.5 years, with earlier onset in fistulizing disease. A third of cases initially mimic pouchitis. Pouchitis is more frequent in left-sided UC and less so in pancolitis. Shorter disease-free survival for de novo-CD in recent years may reflect evolving disease patterns.