BACKGROUND: Inflammatory bowel disease [IBD], encompassing Crohn's disease [CD] and ulcerative colitis [UC], places a high burden on health care resources. To date, no study has assessed the combined direct and indirect cost of IBD in a population-based setting. Our aim was to assess this in a population-based inception cohort with 10 years of follow-up.

METHODS: All incident patients diagnosed with CD or UC, 2003-2004, in a well-defined area of Copenhagen, were followed prospectively until 2015. Direct and indirect costs were retrieved from Danish national registries. Data were compared with a control population [1:20]. Associations between the costs and multiple variables were assessed.

RESULTS: A total of 513 (CD: 213 [42%], UC: 300 [58%]) IBD patients were included. No significant differences were found in indirect costs between CD, UC, and the control population. Costs for CD patients were significantly higher than those for UC regarding all direct expenditures (except for5-aminosalicylates [5-ASA] and diagnostic expenses). Biologics accounted for €1.6 and €0.3 million for CD and UC, respectively. The total costs amounted to €42.6 million. Only patients with extensive colitis had significantly higher direct costs (proctitis: €2273 [1341-4092], left-sided: €3606 [2354-5311], extensive: €4093 [2313-6057], p <0.001). No variables were significantly associated with increased total costs in CD or in UC patients.

CONCLUSIONS: In this prospective population-based cohort, direct costs for IBD remain high. However, indirect costs did not surpass the control population. Total costs were mainly driven by hospitalisation, but indirect costs accounted for a higher percentage overall, although these did decrease over time.

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