S1184 Cumulative Incidence of and Risk Factors for Major Abdominal Surgery in a Population-Based Cohort of Crohn's Disease

S1184 Clock starts at time of Crohn's diagnosis. Cumulative Incidence of and Risk Factors for Major Abdominal Surgery in a Population-Based Cohort of Crohn's Disease Laurent Peyrin Biroulet, Edward V. Loftus, William S. Harmsen, William J. Tremaine, Bruce G. Wolff, John H. Pemberton, Eric J. Dozois, Robert R. Cima, David W. Larson, Alan R. Zinsmeister, William J. Sandborn

S1186 Incidence of Microscopic Colitis in Northern France Mathieu Kohut, Alain Duhamel, Mathurin Flamant, Guillaume Savoye, Julia Salleron, Franck Brazier, Corinne Gower-Rousseau, Eric Lerebours, Antoine Cortot, Jean-Frederic Colombel, Denis Chatelain, Jean-Louis Dupas

Background and aims: We sought to update the cumulative probability of surgery in Crohn's disease in a population-based cohort, and to identify baseline factors associated with need for surgery. Methods: Using the resources of the Rochester Epidemiology Project, the medical records of 310 incident cases of Crohn's disease from Olmsted County, Minnesota, diagnosed between 1970 and 2004, were reviewed through March 2009. Major abdominal surgery was defined as any surgery except perianal surgery or endoscopic dilation. Cumulative incidence was estimated using the Kaplan-Meier method, and associations between baseline factors and time to first event were assessed using proportional hazards regression and expressed as hazard ratios (HR) with 95% confidence intervals (95% CI). Results: Median follow-up per patient (pt) in this cohort was 11.8 years (yrs) (range, 0.1-39 yrs). A total of 152 pts (49%) underwent at least one major abdominal surgery, 65 pts (21%) underwent at least two major abdominal surgeries, and 32 (10%) underwent at least three major abdominal surgeries. The first major abdominal surgery was an ileal or ileocecal resection in 110 out of 152 (72.4%) pts. The mean number of major abdominal surgeries was 0.25 (+/- 1.32) per yr of follow-up. See table for cumulative probabilities (%) with 95% CI of various surgical endpoints at 5, 10, 20, and 30 years. Baseline factors significantly associated with time to first major abdominal surgery were ileocolonic (HR relative to colonic, 3.8; 95% CI, 2.3-6.1), small bowel (HR, 4.3; 95% CI, 2.6-6.9), and upper gastrointestinal (HR, 5.7; 95% CI, 2.3-14) disease; and penetrating (HR, 8.6; 95% CI, 5.8-12.8) and stricturing (HR, 9.4; 95% CI, 5.1-17.1) complications at the time of diagnosis. Conclusion: The cumulative risk of major abdominal surgery in this population-based cohort of Crohn's disease exceeded 60% after 30 years of disease, and many pts required second or third surgeries. Non-colonic disease extent and complicated disease at diagnosis were significantly associated with need for major abdominal surgery. Knowledge of these factors may be useful when developing disease modification trials. Cumulative Probability (%) With 95% CI

Background: Microscopic colitis (MC), comprising collagenous colitis (CC) and lymphocytic colitis (LC) are a common cause of chronic diarrhea. There were no data concerning the incidence of MC in France. Aim: to investigate the incidence of MC in the Somme departement, a geographically defined area in northern France, and to study clinical features and risk factors for both CC and LC. Methods: This population based study was realized trough all gastroenterologists and pathologists of the Somme departement (EPIMAD registry). All new patients, residents of the departement, with a new histopathologic diagnosis of CC or LC between January 1, 2005, and December 31, 2007, were identified. The colonic biopsy specimens from all patients were reviewed by a group of 4 expert gastrointestinal pathologists to assess the diagnosis of CC or LC. Demographic and clinical data were collected from medical records of identified patients. Incidence rate was age and sex adjusted to the French population. Results: During the 3-year study, 130 new cases of MC (87 CC and 43 LC) were identified. The annual incidence rate for MC was 7.9 per100,000 person-years. The annual incidence rates for CC and LC were 5.3 and 2.6 per 100,000 person-years, respectively. The median age at diagnosis was 63 [interquartile range: 50-75] years for MC, 70 [61-78] years for CC and 48 [40-61] years for LC. The sex ratio F:H was 3.5:1 for MC, 4.1:1 for CC, and 2.6:1 for LC. The median interval between onset of symptoms and diagnosis was 8 weeks for both CC [4-13] and LC [4-15]. Chronic diarrhea and abdominal pain were present at diagnosis in 93% and 47% of MC, respectively. Associated autoimmune disease was found in 36 (28%) patients. Prior cholecystectomy (p=0.05), and use of diuretics (p= 0.009) or proton pump inhibitors (p=0.003) were more frequently associated with CC compared to LC. Multivariate analysis showed that only the use of proton pump inhibitors increases the risk of CC. Conclusion: This population based study showed a high incidence of MC in France and confirmed that autoimmune diseases and medications such as proton pump inhibitors could be associated with the development of MC. S1187 Unique Predictors of Chronic Pouch Inflammation Among Ulcerative Colitis Patients With Primary Sclerosing Cholangitis (PSC) Undergoing Ileal PouchAnal Anastomosis (IPAA) Daniel Brelian, Dermot P. McGovern, Marla Dubinsky, Dror Berel, David Q. Shih, Andrew Ippoliti, Eric A. Vasiliauskas, Stephan R. Targan, Phillip Fleshner, Gil Y. Melmed Background: Patients with PSC-associated ulcerative colitis undergoing ileal pouch-anal anastomosis (IPAA) have a higher incidence of chronic pouchitis compared to patients with UC patients without PSC. The aims of this study were to identify additional characteristics distinguishing UC patients with PSC (+PSC) from UC patients without PSC (-PSC), and to assess for predictors of chronic pouch inflammation after IPAA. Methods: Consecutive patients with UC, undergoing IPAA by a single surgeon were prospectively enrolled into a longitudinal cohort. Patient demographics and disease characteristics were assessed. IBD seromarkers (pANCA, ASCA-IgG, ASCA-IgA, OmpC, CBir1, I2) were measured from serum collected before surgery using ELISA and immunofluorescence. Long-term outcomes included acute pouchitis (AP) (antibiotic responsive), chronic pouchitis (CP) (antibiotic dependent or refractory), or de novo Crohn's disease (CD). Chronic pouch inflammation was defined as having the outcome of either CP or CD. A Cox proportional hazards model was used to compare time to pouch inflammation between +PSC and -PSC patients after IPAA. Results: Of the 413 study patients, 18 (4%) were +PSC and 395 (96%) were -PSC. +PSC patients were more likely to have had pancolitis (100% vs 77%; p=0.01) and backwash ileitis (56% vs 12%; p<0.001) than -PSC patients. IPAA was performed for cancer/dysplasia more often in +PSC patients than -PSC patients (39% vs 15%; p=0.03). Compared to -PSC patients, +PSC patients had a higher incidence of pANCA seropositivity (100% vs 69%; p=0.0004), and higher levels of CBir1 (mean 49.6 vs 27.1; p=0.02). Median followup after stoma closure was 11 months (range, 3 to 144 mos) among +PSC and 31 months (1 to 194 mos) among -PSC. +PSC patients had higher rates of AP (73% vs 38%; p=0.0006) and CP (69% vs 38%; p=0.02) than -PSC patients. In addition, +PSC patients developed pouch inflammation more quickly than -PSC patients (mean no. months 4.5 vs. 18.3, hazard ratio 5.2 (95% confidence interval 2.82, 9.59), log-rank p<0.001). The risk of chronic pouch inflammation was significantly increased among +PSC patients if the indication for surgery was medically-refractory

*Clock starts at Crohn's diagnosis. **Clock starts at date of first major abdominal surgery. S1185 Non-Fistulizing Perianal Crohn's Disease in a Population-Based Cohort Laurent Peyrin Biroulet, Edward V. Loftus, William S. Harmsen, Alan R. Zinsmeister, William J. Sandborn Background and Aims: The natural history of non-fistulizing perianal Crohn's disease is unknown. Methods: Using the resources of the Rochester Epidemiology Project, the medical records of 310 incident cases of Crohn's disease from Olmsted County, Minnesota, diagnosed between 1970 and 2004, were reviewed through July 2009 for evidence of non-fistulizing perianal disease. Cumulative incidence was estimated using the Kaplan-Meier method, and associations between baseline factors and time to first event were assessed using proportional hazards regression and expressed as hazard ratios (HR) with 95% confidence intervals (CI). Four types of lesions were studied: anorectal strictures, deep ulcers, fissures, and skin tags. Results: See table for cumulative probabilities (95% CI) of various perianal lesions from time of diagnosis. Factors associated with anorectal strictures were thiopurines (HR, 5.9; 95%CI, 1.7-20.8) and antibiotics (HR, 4.9; 95%CI, 1.8-13.6) use within 90 days after diagnosis (early use). The only factor associated with anal ulcers was the presence of extraintestinal manifestations (HR, 2.9; 95%CI, 1.2-7.2). The factors associated with skin tags were male gender (HR, 0.34; 95%CI, 0.2-0.6), former smoking status relative to never (HR, 0.2; 95%CI, 0.05-0.9), presence of extraintestinal manifestations (HR, 2.9; 95%CI,

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AGA Abstracts

AGA Abstracts

1.7-5), and early aminosalicylates (HR, 2.3; 95%CI, 1.1-4.7) and antibiotics use (HR, 2.8; 95%CI, 1.1-7.2). Baseline factors associated with time to first non-fistulizing perianal lesion were age (HR, 0.98; 95%CI, 0.97-0.99), male gender (HR, 0.5; 95%CI, 0.4-0.8), presence of extraintestinal manifestations (HR, 2; 95%CI, 1.2-3.3), and early aminosalicylate (HR, 1.8; 95%CI, 1.1-3.1) and antibiotic (HR, 2.6; 95%CI, 1.1-6.1) use. Conclusion: Nonfistulizing perianal lesions occurred frequently during the clinical course of Crohn's disease in this population-based cohort (cumulative risk of almost 30% at 10 years). Males were less likely to develop anal tags, while those with extraintestinal manifestations at baseline were more likely to develop ulcers and tags. Cumulative Probabilities (%) With 95% CI