Long-Term Bowel Function and Fate of the Ileal Pouch after Restorative Proctocolectomy in Patients with Crohn's Disease: A Systematic Review with Meta-Analysis and Metaregression

Background and Aims: Debate exists on whether ileal pouch anal anastomosis [IPAA] can be safely offered to patients diagnosed with Crohn's disease [CD]. Our aim was to assess the outcome of IPAA for CD vs ulcerative colitis [UC]. Methods: We used a PRISMA/MOOSE-compliant meta-analysis. Studies published between 1993 and 2018 were retrieved. Primary end points included complications. Secondary endpoints included functional outcome. The time of CD diagnosis was considered [intentional vs incidental IPAA]. Results: Eleven studies comprising 6770 patients [CD = 352, UC = 6418] were included, with 44-120 months of follow-up. Pouch fistulae were more common in CD (CD vs UC; odds ratio (OR) 6.08; p = 0.0003, GRADE+++), as were strictures [OR 1.82; p = 0.02, GRADE+++] and failure [OR 5.27; p < 0.0001, GRADE++++]. Compared with UC, postoperative CD diagnosis was associated with a much higher risk of fistulae [OR 6.23; p = 0.006, GRADE+++] and failure [OR 8.53; p < 0.0001, GRADE++++] than intentional IPAA in CD [fistula: OR 4.17; p = 0.04, GRADE+++; failure: OR 2.48; p = 0.009, GRADE++++]. Age at surgery was positively associated with failure in CD [p = 0.007]. Obstruction was more common after intentional IPAA for CD. The risk of pouchitis did not differ between CD and UC [OR 1.07, p = 0.76, GRADE+++]. CD patients were at a higher risk of seepage [OR 2.27; p = 0.010, GRADE++]. Conclusions: Patients with CD have 5-fold higher risk of failure, and a 2-fold risk of strictures after IPAA compared with UC. The risk is much higher if diagnosis is performed after IPAA. Function in those who retain the pouch seemed similar to that of patients with UC. CD does not increase the risk of pouchitis. IPAA could be offered to a selected population of CD patients after proper preoperative counselling.