Endoscopic Normalization and Transition of J-Pouch Phenotypes Over Time in Patients With Inflammatory Bowel Disease.

Background: Patients with inflammatory bowel disease (IBD) who undergo proctocolectomy with ileal pouch-anal anastomosis may develop pouchitis. We previously proposed a novel endoscopic classification of pouchitis describing 7 phenotypes with differing outcomes. This study assessed phenotype transitions over time.

Methods: We classified pouch findings into 7 main phenotypes: (1) normal, (2) afferent limb (AL) involvement, (3) inlet (IL) involvement, (4) diffuse, (5) focal inflammation of the pouch body, (6) cuffitis, and (7) pouch-related fistulas noted more than 6 months after ileostomy takedown. Among 2 endoscopic phenotypes, the phenotype that was first identified was defined as the primary phenotype, and the phenotype observed later was defined as the subsequent phenotype.

Results: We retrospectively reviewed 1359 pouchoscopies from 426 patients (90% preoperative diagnosis of ulcerative colitis). The frequency of primary phenotype was 31% for AL involvement, 42% for IL involvement, 28% for diffuse inflammation, 72% for focal inflammation, 45% for cuffitis, 18% for pouch-related fistulas, and 28% for normal pouch. The most common subsequent phenotype was focal inflammation (64.8%), followed by IL involvement (38.6%), cuffitis (37.8%), AL involvement (25.6%), diffuse inflammation (23.8%), normal pouch (22.8%), and pouch-related fistulas (11.9%). Subsequent diffuse inflammation, pouch-related fistulas, and AL or IL stenoses significantly increased the pouch excision risk. Patients who achieved subsequent normal pouch were less likely to have pouch excision than those who did not (8.1% vs 15.7%; P = .15).

Conclusions: Pouch phenotype and the risk of pouch loss can change over time. In patients with pouch inflammation, subsequent pouch normalization is feasible and associated with favorable outcome.