Epidemiology and socio-economic aspects of chronic inflammatory bowel diseases in Switzerland Abstract. Inflammatory bowel diseases (IBD) are comprised of Crohn's disease and ulcerative colitis. Both diseases are diagnosed with increasing frequency over the last few decades in industrialized countries. Current, population-based data from Switzerland show a prevalence of 0.4 % for IBD in Switzerland (one affected person in 250 inhabitants) with equal shares for Crohn's disease and ulcerative colitis (one affected person in 500 inhabitants each). The mortality rate of Swiss IBD patients is comparable with the one of patients without IBD. Roughly 80 % of patients with IBD suffer from co-morbidities. The most frequent co-morbidities concern cardiovascular diseases, followed by rheumatologic conditions, acid-related disorders, pain, and psychologic disorders. The yearly costs for the care of IBD patients are constantly increasing. The biggest proportion of the annual costs for IBD care is related to outpatient costs of which drug costs represent the major cost driver.