Real-world evidence on medication patterns in inflammatory bowel disease the first decade after diagnosis

BACKGROUND AND AIMS: Medical treatment of inflammatory bowel disease (IBD) is complex and highly dynamic. This study conducts an extensive population-wide analysis of real-world treatment patterns in ulcerative colitis (UC) and Crohn's disease (CD) to provide population-based estimates to patients, clinicians, and healthcare systems. METHODS: Using Danish nationwide registers, we followed individuals diagnosed with IBD during 2003-2023 in Denmark for up to 10 years. Focusing on 5-aminosalicylic acid (5-ASA), corticosteroids, methotrexate, thiopurines, and advanced therapies (biological and small molecule drugs), we examined cumulative use, use per year after diagnosis, and treatment combinations. Analyses were stratified on sex, age, and calendar year at diagnosis. RESULTS: In 36 179 individuals with IBD (25 870 UC; 10 309 CD), the 10-year cumulative use of immunomodulators and/or advanced therapies was 37.0% in UC and 74.9% in CD. Long-term treatment was dominated by advanced therapies in CD and 5-ASA in UC. The cumulative use of corticosteroids in UC and 5-ASA in CD declined in recent years, whereas the use of advanced therapies rose in both UC and CD. The use of advanced therapies decreased with increasing age at diagnosis. In the tenth year after diagnosis, approximately half of patients (UC: 43.8% and CD: 50.8%) did not receive any medication. CONCLUSIONS: In this population-based real-world medication study, we observed that 5-ASA remains the mainstay of treatment for UC, whereas advanced therapies dominate long-term treatment for CD. Of note, half of patients did not receive any medical treatment in the tenth year after diagnosis.