Retrospective Observational Multicenter Study on the Treatment Patterns, Extra-Intestinal Manifestations, Resource Utilisation, and Outcomes of Patients With Inflammatory Bowel Disease in Dutch Hospitals

This multicenter retrospective real-world data study will evaluate the treatment pathways and disease burden of adult patients with Crohn's disease (CD) and ulcerative colitis (UC) treated in 5-10 Dutch hospitals between 2018 and 2026. The study will assess: * Treatment sequences, switching patterns, and treatment duration * Prevalence and incidence of extra-intestinal manifestations (EIMs) * Healthcare resource utilization (hospitalizations, outpatient visits, endoscopies, surgery, and length of stay) * Direct healthcare costs * Availability of disease activity biomarkers Using linked administrative, prescription, procedure, and laboratory data, outcomes will be analyzed by age, line of therapy, and clinical characteristics. Special focus will be placed on the impact of EIMs on treatment patterns, healthcare utilization, and costs. The findings will provide real-world evidence on IBD management in the Netherlands and support clinical decision-making, healthcare planning, and future research on treatment optimization and coexisting immune-mediated conditions.