S902 Assessing the Impact of Interval Duration Between Ileal Pouch Creation and Loop Ileostomy Closure on the Development of Subsequent Inflammatory Pouch Conditions in Patients with Ulcerative Colitis

Introduction: The prime surgical management strategy for medically refractory ulcerative colitis (UC) is an ileal pouch – anal anastomosis (IPAA). Surgical practice often includes the creation of a temporary loop ileostomy (LI) with subsequent closure. The impact of the interval between IPAA and LI closure regarding endoscopic pouch inflammation has not been well defined. The aim for this project was to assess if delayed LI closure places patients at higher risk of endoscopic inflammatory pouch diseases (EIPD). Methods: This is a retrospective cohort study that assessed patients with UC that underwent IPAA with LI closure between January 2010 and December 2020. Patients were divided into 2 groups - early (0-118 days) or late closure (greater than 180 days) – based on interval between IPAA and LI closure. The primary outcome was development of EIPD, which was a composite of pouch disease activity index (PDAI) score of greater than or equal to 4, mucosal breaks not limited to anastomotic lines, or diffuse pouch inflammation. Secondary outcomes included development of strictures, fistulas, inflammation of the rectal cuff, and individual components of the primary outcome. Results: 379 patients were included in the analysis. Controlling for other factors, multivariable logistic regression analysis showed that patients that underwent late closure had greater odds of developing EIPD compared to patients that underwent early closure (OR = 1.92, 95% CI 1.06, 3.51, P = 0.033). The late closure group also had higher odds of having strictures (pouch, pouch inlet, neoterminal ileum) or fistulas (perianal, anal-vaginal, pouch vaginal, entero-enteric, enterovaginal, tip of J/efferent limb) than the early closure group (OR = 2.42, 95% CI 1.09,5.23, P = 0.026). In contrast, longer duration of IBD prior to surgery was protective against the development of EIPD and complications. Of the patients in the late-closure group, 29 (40%) patients had delayed closure due to non-medical reasons (patient preference), 16 (22%) had delayed closure for infectious complications (sepsis, abscess, leak), and the remaining 28 (38%) had delayed closure due to non-infectious medical reasons (cancer therapy, fistula repair) (Table 1). Conclusion: Patients with a late LI closure had a higher odds of developing EIPD, strictures and fistulas as compared to early closure. Post-operative complications leading to LI closure delay may affect the future development of EIPD and IPAA complications. Table 1. - Multivariable Logistic Regression for Development of Endoscopic Pouch Inflammation Characteristic OR 95% CI P-value Time Between IPAA and ileostomy closureEarlyLate 1.92 1.06, 3.51 0.033 History of PSCNoYes 0.33 0.10,1.00 0.061 Extraintestinal ManifestationsNoYes 2.50 1.48, 4.27 < 0.001 IBD DistributionPan-colitisLeft Sided Colitis/Proctitis 0.58 0.25,1.25 0.178 Pre-Surgery BMIUnderweight/Normal WeightOverweight 0.62 0.36,1.05 0.076 Duration of IBD Prior to Colectomy (Years) 0.96 0.93, 0.99 0.018