P597 The changing landscape of paediatric Inflammatory Bowel Disease medication in Australia 2015-2021, A population-based study

Abstract Background There have been significant advancements in the pharmaceutical management of paediatric inflammatory bowel disease (IBD) with cost and clinical implications. The real-world shifts in prescribing habits in Australia have yet to be characterised. As part of the National Inflammatory Bowel Disease Paediatric Quality of Care project, this study sought to examine patterns of IBD-related medication use in the Australian paediatric population from 2015 to 2021. Methods We used Services Australia Pharmaceutical Benefits Scheme 10% data to identify prescriptions for paediatric IBD patients from 1/1/2015 to 31/12/2021. In Australia, select prescribers must specify an authorised indication for the government subsidy of authority-required medications (i.e. aminosalicylates (5-ASAs) and biologics), enabling patients to be tagged with Crohn’s disease (CD) or ulcerative colitis (UC). To be included in the analysis, patients must have received at least one prescription of an authority-required medication and be aged between 0 and 17 years at the time of dispensing their first IBD-related medication. Trends over time were assessed for significance with the chi-squared test for trend. Results The data identified 2940 UC patients (mean age 14.09 ± 3.15) and 2840 CD patients (mean age 14.20 ± 2.67) across 2015-2021. In 2015, 54.90% of IBD patients were dispensed at least one prescription of corticosteroids (CCSs). Trends showed CCS use to fall dramatically to only 29.27% of patients in 2021 (p < 0.0001). Among CD patients on azathioprine (AZA) treatment, there was a disproportionate decrease in male usage, with the male CD patients on AZA falling from 47% (n=277) in 2015 to 38% (n=167) in 2021 (p < 0.0001). Simultaneously, CD patients on methotrexate rose from 11% (n=130) to 28% (n=330) (p < 0.0001). Biologic use rose continually among both CD and UC patients. CD patients on infliximab (IFX) rose from 34% (n=420) in 2015 to 59% (n=670) in 2021 (p < 0.0001), whilst UC patients on IFX increased from 5% (n=70) to 24% (n=220) over the same time (p < 0.0001). Despite rising patient numbers, the total estimated government expenditure on IFX for CD decreased by over 50% from AUD 7.1 million in 2015 to AUD 3.4 million in 2021. Conclusion This study quantifies the temporal trends in prescribing habits for paediatric IBD in Australia, observing a shift towards increasingly biologic-centred therapy. Despite increasing IFX use in CD, government expenditure decreased, suggesting that escalated medication use in paediatric IBD care does not necessarily lead to increased costs over time.