P337 Low seroprevalence of celiac disease in a large screening study in unselected Swiss IBD cohort patients

Abstract Background Several systematic screening studies in the general population indicate a high number of unrecognised cases of Celiac disease (CeD). According to clinical experience and shared risk gene loci CeD and inflammatory bowel disease (IBD) may be associated conditions. However, the exact prevalence of asymptomatic and unrecognised CeD in IBD has not been systematically investigated on the large scale. Methods We performed a large screening-study of the CeD seroprevalence in unselected IBD patients from the Swiss IBD Cohort study (SIBDCS). Anti-tissue transglutaminase (a-TTG) antibody IgA, anti-deamidated gliadin peptide IgG (g-DGP) and total serum immunoglobulin A were measured. Results In total serum samples of 2019 IBD patients (median disease duration 12 years, median age at enrolment into the SIBDCS 38 years, median BMI 24 kg/m2)were analysed, among them 1150 (57.3%) with Crohn’s disease (CD), 812 (40.5%) with ulcerative colitis UC and 45 (2.2%) with IBD unclassified (IBDu). In 8 (4 per mille) of the 2019 randomly selected SIBDCS patients a diagnosis of CeD had been established previously. Amongst the remaining 2011 IBD patients without CeD we found a seroprevalence of 1.5 per mille (0.149%) for a-TTG—the classical screening test in the absence of IgA deficiency—and 1 per mille (0.099%) for g-DGP. IgA deficiency (defined as