Endoscopic Phenotype of the J Pouch in Patients With Inflammatory Bowel Disease: A New Classification for Pouch Outcomes

Abstract

Background & aims: Pouchitis is a common complication of ileal pouch-anal anastomosis (IPAA) in patients with ulcerative colitis who have undergone colectomy. Pouchitis has been considered a single entity despite a broad array of clinical and endoscopic patterns. We developed a novel classification system based on the pattern of inflammation observed in pouches and evaluated the contributing factors and prognosis of each phenotype.

Methods: We identified 426 patients (384 with ulcerative colitis) treated with proctocolectomy and IPAA who subsequently underwent pouchoscopies at the University of Chicago between June 1997 and December 2019. We retrospectively reviewed 1359 pouchoscopies and classified them into 7 main pouch phenotypes: (1) normal, (2) afferent limb involvement, (3) inlet involvement, (4) diffuse, (5) focal inflammation of the pouch body, (6) cuffitis, and (7) pouch with fistulas noted 6 months after ileostomy takedown. Logistic regression analysis was used to assess factors contributing to each phenotype. Pouch survival was estimated by the log-rank test and the Cox proportional hazards model.

Results: Significant contributing factors for afferent limb involvement were a body mass index of 25 or higher and hand-sewn anastomosis, for inlet involvement the significant contributing factor was male sex; for diffuse inflammation the significant contributing factors were extensive colitis and preoperative use of anti-tumor necrosis factor drugs, for cuffitis the significant contributing factors were stapled anastomosis and preoperative Clostridioides difficile infection. Inlet stenosis, diffuse inflammation, and cuffitis significantly increased the risk of pouch excision. Diffuse inflammation was associated independently with pouch excision (hazard ratio, 2.69; 95% CI, 1.34-5.41; P = .005).

Conclusions: We describe 7 unique IPAA phenotypes with different contributing factors and outcomes, and propose a new classification system for pouch management and future interventional studies.

Keywords: Endoscopic Phenotype; Ileal Pouch–Anal Anastomosis; Inflammatory Bowel Disease; Pouch Prognosis; Pouchitis.

Figure 1.

Endoscopic phenotype of the pouch (The proposed Chicago Classification). (A) normal pouch, (B) afferent limb involvement, (C) inlet involvement, (D) diffuse inflammation of the pouch body, (E) focal inflammation of the pouch body, (F) cuffitis, (G) pouch with fistulas ≥6 months after ileostomy takedown.

Figure 2.

Kaplan-Meier curves to evaluate pouch survival for (A) overall population, (B) afferent limb involvement, (C) inlet involvement, (D) diffuse inflammation of the pouch body, (E) focal inflammation of the pouch body, (F) cuffitis, and (G) pouch with fistulas developed ≥6 months after ileostomy takedown.

Figure 3.

Kaplan-Meier curves to evaluate pouch survival for (A) afferent limb ulcers, (B) afferent limb stenosis, (C) inlet ulcers, and (D) inlet stenosis.