The American Journal of GASTROENTEROLOGY VOLUME 110 | SUPPLEMENT 1 | OCTOBER 2015 www.amjgastro.com Abstracts S816 pouchoscopy on the same day as ileostomy takedown. One case and one control had undergone J pouch creation but not ileostomy takedown. Te most frequent indication for J pouch surgery was medically refractory disease. Cases and controls were similar in baseline characteristics; cases were more likely to have undergone stapled anastomoses and had a shorter duration of follow-up (Table 1). Most pouchosco- pies were performed on a routine basis (n=145, 95.4%). Half (n=75) of all pouchoscopies were reported as normal. Common abnormal endoscopy fndings included stricture (n=53, 35.3%), pouchitis (n=13, 8.7%), and cuftis (n=1, 0.7%). All patients with strictures were dilated at the time. Length of stay dur- ing ileostomy takedown hospitalization was shorter for cases than controls. However, neither short- nor long-term complications were statistically diferent between cases and controls (Table 2). Additionally, abnormalities on pouchoscopy were not predictive for either short- (p=0.75) or long-term complications (p=0.57). Pouchoscopy delayed ileostomy takedown surgery in 4 patients, all of whom were symptomatic or had recognized complications prior to pouchoscopy. Conclusion: Pouchoscopy prior to ileostomy takedown was common in our institutional experience. Although rates of abnormalities on pouchoscopy (mostly strictures) were frequent, ileostomy takedown was rarely delayed and there was no association with future complications. Pouchoscopy prior to ileos- tomy takedown probably has greatest utility in symptomatic patients. 1920 Higher Tioguanine Metabolite Levels Improve Long-Term Outcomes in Patients With Infammatory Bowel Diseases Presidential Poster Andres Yarur, MD 1 , Bilal Gondal, MD, MRCSI 2 , Nayab Syed 1 , Ayal Hirsch, MD 2 , Britt Christensen, MD 2 , Russell Cohen, MD, FACG 2 , David T. Rubin, MD 2 . 1. University of Chicago, Chicago, IL; 2. University of Chicago Medicine, Chicago, IL. Introduction: 6-thioguanine nucleotide (6TGN) is a sub-metabolite of azathioprine (AZA)/6-mercap- topurine (6MP) that has been associated with clinical efcacy in cross-sectional studies of infammatory bowel disease (IBD) patients, but its efect on long-term outcomes is unknown. Te aim of this study was to assess whether 6TGN levels throughout treatment course were associated with improved long-term outcomes in patients with IBD. [1919] Table 1. Patient and Surgical Characteristics Cases N=152 Controls N=33 P-value Mean age, years (±s.d.) 46.2 (±14.7) 42.8 (±13.7) 0.21 Male gender, n (%) 79 (52.0) 12 (36.4) 0.10 IBDU primary diagnosis, n (%) 8 (5.3) 2 (6.1) 0.86 Indication for J pouch, n (%) Refractory disease 113 (74.3) 28 (84.9) 0.15 Dysplasia/malignancy 31 (20.4) 3 (9.1) 0.07 Length of follow-up, median days 417 669 0.03 a Gastrograffin enema, n (%) 114 (77.0) 20 (64.5) 0.19 Open procedure, n (%) 97 (63.8) 24 (75.0) 0.21 Stapled anastomosis, n (%) 127 (83.6) 20 (62.5) 0.03 a a Statistically significant. [1919] Table 2. Outcome Measures Cases N=152 Controls N=33 P-value Short-term complications, n (%) 27 (18.6) 11 (36.7) 0.07 Small bowel obstruction/ileus 12 (8.3) 2 (6.7) 0.76 Infection 3 (2.1) 2 (6.7) 0.34 Long-term complications, n (%) 84 (67.7) 18 (72.0) 0.68 Pouchitis 24 (19.4) 7 (28.0) 0.39 Readmission within 30 days 6 (4.9) 1 (4.0) 0.85 Pouch removal 2 (1.6) 3 (12.0) 0.14 Stricture 2 (1.6) 1 (4.0) 0.57 Length of stay for ileostomy takedown surgery, median days 4 5 0.001 a Median days between J pouch creation and ileostomy takedown 96 91 0.20 a Statistically significant. [1920] Table 1. Baseline characteristics in IBD patients with 6-TGN levels with complications or without complications a Variable Long term compli- cations a No long term compli- cations a P Value Age (mean in years, s.d.) 37 (16) 34 (13) 0.29 Body mass (mean in Kg, s.d.) 70.1 (18.5) 73.8 (18.5) 0.64 Time on thiopurine (mean in months, s.d.) 28 (48.6) 22.7 (27.3) 0.59 Thiopurine methyltrans- ferase (mean in units/ml RBCs, s.d.) 19.7 (8) 23.4 (8) 0.39 Diagnosis of Crohn´s disease (n,%) 25 (62.5) 15 (37.5) 0.33 Phenotype of Crohn’s disease patients Ileo-colonic (n,%) 16 (64) 9 (36) 0.28 Small bowel disease (n,%) 6 (24) 19 (76) 0.35 Colonic disease (n,%) 4 (16) 21 (84) 0.89 Stricturing phenotype (n,%) 12 (48) 13 (52) 0.15 Penetrating disease (n,%) 7 (28) 18 (72) 0.41 Phenotype of ulcerative colitis patients Proctitis (n,%) 2 (13.3) 13 (86.7) 0.17 Left-sided colitis (n,%) 7 (46.7) 8 (53.3) 0.23 Pan-colitis (n,%) 7 (46.7) 8 (53.3) 0.39 a complications defined as disease relapse (needing steroids or biologics or being hospitalized) or IBD-related surgery. [1920] Table 2. 6-TGN levels throughout therapy and development of complications* Complication a No complication a P value Nadir 6TGN level (mean, s.d.) 144.8 (93.6) 197.1 (121.7) 0.03 Mean 6TGN level (mean, s.d.) 177.2 (90.3) 223.9 (120.5) 0.047 Peak 6TGN level (mean, s.d.) 219.3 (122.7) 251.7 (137.4) 0.26 a complications defined as disease relapse (needing steroids or biologics or being hospitalized) or IBD-related surgery. [1920A] Figure 1.