Burden of disease and increasing prevalence of inflammatory bowel disease in a population-based cohort in the Netherlands.

Background Reported epidemiology and phenotype distributions vary widely and disease burden of inflammatory bowel disease (IBD) is poorly described. Our aim was to establish these features in a population-based cohort covering 319 976 inhabitants. Furthermore, differences between tertiary referral and peripheral hospital patients were quantified. Methods IBD patients in the adherence area of three peripheral hospitals (2004-2012) were included. Medical and surgical treatment data were obtained. Quality of life and disease activity were evaluated. An outpatient cohort from a tertiary referral centre was accrued. Results A total of 1461 patients were included: 761 (52.1%) with ulcerative colitis (UC), 579 (39.5%) with Crohn's disease (CD) and 121 (8.3%) with IBD-unspecified. Point prevalence of IBD was 432.1 per 100 000 inhabitants in 2010, which increased significantly over time, P-value of less than 0.0001. The mean annual incidence was 17.2 for UC, 10.5 for CD and 2.2 for IBD-unspecified. Tertiary referral Crohn's patients used thiopurines and biological therapy and underwent surgery significantly more often than patients in peripheral hospitals (P<0.0001). Disease activity correlated negatively with quality of life (P<0.0001) in UC and CD. Conclusion The prevalence of IBD is still increasing. Burden of disease was significantly more severe, mainly in Crohn's patients, in the referral centre, highlighting the importance of population-based studies to accurately describe phenotype distribution and disease burden. Copyright (C) 2016 Wolters Kluwer Health, Inc. All rights reserved.