Health care costs and their predictors of inflammatory bowel diseases in Germany

Detailed cost studies of inflammatory bowel diseases (IBD) for Germany are limited. Aim of this study was to collect resource-use data related to IBD via a cross-sectional study, to quantify these from the perspective of the Statutory Health Insurance (SHI) and to identify cost-driving factors. Patients with Crohn's disease (CD) or ulcerative colitis (UC) from 24 gastroenterological specialists' practices and two hospitals were enrolled in an internet-based database between March 2006 and July 2007. Outpatient services, inpatient visits as well as medication usage were recorded and evaluated from the perspective of the SHI for 2007. Disease severity was measured by the Crohn's Disease Activity Index (CDAI) and the Colitis Activity Index (CAI), respectively. Extensive statistical analyses including generalized linear modeling (gamma model with the log link) to identify cost-driving factors were performed. Data from 1,030 patients with IBD (CD: 511; UC: 519) were collected. On average a patient with CD incurs annual costs of EUR 3,767 (+/- 5,895 (SD)) (among those 68.5% medication; 20.5% inpatient) and an average patient with UC incurs EUR 2,478 (+/- 4,591) (74% medication; 10% inpatient), whereas 10% of the patient with IBD account for 49% (CD: 50%; UC: 46%) of the costs. The regression analysis showed that especially the use of TNF-alpha-inhibitors, inpatient stays, gender as well as the severity status has a significant influence on costs. Further disease-specific impact factors were identified. This is the first study to calculate costs due to CD and UC from the perspective of the SHI in Germany and to identify cost-driving factors. It confirms a high economic burden of IBD to payers and society.