Table 1.

Study characteristics of patients with a normal or Crohn’s disease of the pouch following ileo pouch-anal anastomosis for ulcerative colitis

Author, year	Study period	Number of patients with normal pouch or CDP, n	Normal pouch, n [%]	CDP, n [%]	Type of pouch, n [%]	IPAA surgical approach, n [%]	Follow-up period after IPAA	Diagnostic criteria of CDP	CDP features and presentation [n]
Shen et al.35 2005	May 2002 to January 2004	49	26 [53%]	23 [47%]	J-pouch, 44/49 [90%]	Two-stage, 40/49 [82%]	—	Presence of non-surgery-related perianal fistulas, inflammation or ulcerations at the afferent limb or small bowel in the absence of NSAID use or granulomas on histology	Bowel obstructive symptoms such as nausea, vomiting, constipation. Histology consistent with pyloric gland metaplasia [4/23], pouchitis [1/22] and cuffitis [1/21]
Tyler et al.36 2013	2007–2010	596	487 [82%]	109 [18%]	—	—	—	At least one of: [a] development of a perianal fistula >1 year after ileostomy closure; [b] stricture proximal to pouch not related to a surgical complication and confirmed by endoscopy or small bowel imaging; [c] inflammation [ulceration, erythema, friability] in afferent limb/pre-pouch ileum or more proximal small bowel on pouchoscopy or upper endoscopy	Fistula [62/109] developed more than 1 year after surgery, inflammation extending to afferent limb [40/109], both fistula and inflammation [7/109]
Truta et al.37 2014	January 2008 to June 2011	39	19 [49%]	20 [51%]	—	One-stage, 10/39 [26%] Two-stage, 23/39 [59%] Three-stage, 6/39 [15%]	—	At least one of: [a] inflammation or ulcerations in small bowel or afferent limb proximal to pouch [excluding backwash ileitis], [b] ulcerated strictures in small bowel or pouch, [c] occurrence of a fistula [perianal, cutaneous, vaginal, bladder] in the absence of surgical-related complications or NSAID use at least 3 months after pouch formation and subsequent ileostomy closure	Inflammation and/or ulcers in pouch [20/20]. Extension of inflammation to terminal ileum [5/20], fistula with adjacent structures [9/20] and endoscopic lesions in stomach, duodenum and distal small bowel [8/20]
Shannon et al.38 2016	1982–1997	72	52 [72%]	20 [28%]	J-pouch, 48/72 [67%] S-pouch, 24/72 [33%]	One-stage, 2/70 [3%] Two-stage, 39/70 [56%] Three-stage, 29/70 [41%]	Median 20 years [range 15–28]	A combination of the following clinical and/or pathological findings: endoscopy with histological samples during a surgical procedure via radiographic imaging or using serological markers of IBD	Fistulizing disease of the pouch [12/20]
Yanai et al.39 2017	1981–2013	188	71 [38%]	117* [62%]	J-pouch, 188/188 [100%]	—	Mean 14 ± 7.4 years	At least one of: pouch-related fistula occurring more than 1 year after ileostomy closure, inflammation of the afferent limb or more proximal small bowel, or fibrostenotic disease of the pouch	—
Barnes et al.40 2020	January 2012 to October 2018	278	86 [31%]	192 [69%]	—	—	12 months	A diagnosis of CDP is per the discretion of the treating physician	—
Li et al.41 2021	1996–2018	52	26 [50%]	26 [50%]	J-pouch, 52/52 [100%]	—	Mean 122 months [range 20–322]	—	Pouch ulceration [14/26], duodenal inflammation [4/26], small bowel inflammation [17/26], pre-pouch ileitis [14/26], stricture [7/26], fistula [11/26], fissure [3/26], granulomas [6/26] and other extraintestinal manifestations [5/26]

CD, Crohn’s disease; CDP, Crohn’s disease of the pouch; IBD, inflammatory bowel disease; IPAA, ileo pouch-anal anastomosis; NSAID, non-steroidal anti-inflammatory drug; UC, ulcerative colitis

*Includes patients with chronic pouchitis.