Background
Paediatric-onset and elderly-onset inflammatory bowel disease (IBD) present unique treatment challenges.

Aims
We investigated treatment patterns following a first and second course of systemic steroids in paediatric- and elderly-onset IBD and compared them to adult-onset IBD.

Methods
All patients diagnosed with Crohn's disease (CD) or ulcerative colitis (UC) between 2000 and 2018 were identified through the Danish healthcare registries. Patients were divided into groups based on their age at diagnosis. Kaplan–Meier plots were prepared for medications and surgeries after diagnosis and after the first and second courses of systemic steroids. Hazard ratios (HR) and 95% confidence intervals (CI) were calculated using multivariate Cox regression analysis for steroid-sparing medications.

Results
1851 CD (13%) and 1687 (6%) UC patients were paediatric-onset, while 2952 (20%) CD and 5812 (23%) UC patients were elderly-onset. Paediatric-onset more frequently received immunomodulators [CD: HR: 1.64, CI: 1.52–1.77, UC: HR: 2.29, CI: 2.02–2.61] and biologics [CD: HR: 1.43, CI: 1.25–1.65, UC: HR: 1.27, CI: 0.99–1.64], while elderly-onset less frequently received immunomodulators [CD: HR: 0.39, CI: 0.35–0.44, UC: HR: 0.58, CI: 0.50–0.67] and biologics [CD: HR: 0.19, CI: 0.14–0.25, UC: HR: 0.36, CI: 0.27–0.48] compared to adult-onset age groups. After two courses of systemic steroids, elderly-onset still received less steroid-sparing medications. High frailty was associated with lower usage of medications for elderly-onset.

Conclusion
There are significant differences in the use of steroid-sparing medication between age of onset, even after two courses with systemic steroids. High frailty could account for some of these differences in elderly-onset IBD.