BACKGROUND: The diagnostic delay in inflammatory bowel disease (IBD) is well known, yet the costs associated with diagnoses before IBD diagnosis have not yet been reported. This study explored societal costs and disease diagnoses 10 years before Crohn's disease (CD) and ulcerative colitis (UC) diagnosis in Denmark.

METHODS: This national register study included patients diagnosed between 2003 and 2015 identified in the Danish National Patient Registry (NPR) and controls who were individually matched on age and sex from the general population. Societal costs included health care services, prescription medicine, home care services, and labor productivity loss. Prediagnostic hospital contact occurring before CD or UC diagnosis was identified using the NPR. Average annual costs per individual were calculated before the patient's first CD or UC diagnosis. A 1-sample t test was then applied to determine significance in differences between cases and controls.

RESULTS: Among CD (n = 9019) and UC patients (n = 20,913) the average societal costs were higher throughout the entire 10-year period before the diagnosis date compared with the general population. The difference increased over time and equaled €404 for CD patients and €516 for UC patients 10 years before diagnosis and €3377 and €2960, respectively, in the year before diagnosis. Crohn's disease and UC patients had significantly more diagnoses before their CD and UC diagnosis compared with the general population.

CONCLUSIONS: Compared with the general population, the societal costs and number of additional diagnoses among CD and UC patients were substantially higher in the 10-year period before diagnosis.