P0906 A comparison of the transport-related carbon footprint of intravenous versus subcutaneous infliximab
Authors: Cartledge A , Carbery I , Broglio G , Greer D , Selinger C 
Published: January 2025

Abstract

Background
Climate change poses a major threat to health and the planet. The United Kingdom’s (UK) National Health Service is thought to account for 5.9% of total UK carbon emissions (1,2). Inflammatory bowel disease (IBD) affects an estimated 500,000 people in the UK (3). Infliximab, a commonly prescribed biological medication for the management of IBD, is available as intravenous (IV) and subcutaneous (SC) preparations. There are numerous benefits to switching patients to SC infliximab (4), but the impact on carbon footprint has not been fully assessed. We aimed to compare the transport-related carbon footprint of IV versus SC infliximab.

Methods
We analysed data from all adult patients with IBD at Leeds Teaching Hospitals Trust who were eligible to switch from IV to SC infliximab. This included all patients on standard dosing (5mg/kg 8 weekly). Carbon footprint of transport for infliximab was calculated from UK port to the infusion unit for IV or patient’s home for SC. Carbon footprint of patient travel was calculated using distance from patient’s home to the infusion unit and mode of transport from local survey data. Carbon emissions were calculated based on distance travelled, type of vehicle, number of units transported, and weight of units transported. Greenhouse gas conversion factors were used to calculate all carbon emission factors. We then compared the calculated 48-week carbon footprint by intention-to-treat (ITT) (i.e. if all patients had switched from IV to SC) and as-treated (AT) (comparing all on IV pre-switch to some on IV and some SC post switch).

Results
169 patients were eligible to switch to SC infliximab and 98 (58%) switched within 3 months. One patient was excluded from analysis as they subsequently moved out of area. Average transport-related carbon footprint was 6.10kgCO2e for IV infliximab and 0.018kgCO2e for SC infliximab per dose, per patient. In the Leeds cohort, over 48 weeks, the transport-related carbon footprint before the switch (168 patients IV) was 6150kgCO2e. Following the switch, the transport-related carbon footprint by ITT analysis (168 patients SC) would have been 71.3kgCO2e and was 2457kgCO2e in the AT analysis (70 patients IV = 2416kgCO2e, 98 patients SC = 41.6kgCO2e SC).

Conclusion
The use of SC infliximab reduces the carbon footprint associated with transport when compared to IV infliximab delivered at an infusion unit. It is important to note that whilst the transport-related carbon footprint is reduced by switching from IV to SC, a full life cycle assessment including analysis of preparing and administering each form of infliximab is still required to fully understand the impact of switching from IV to SC infliximab on carbon footprint.

References
1.NHS England. Delivering a 'Net Zero' National Health Service. 2020.
2.Pichler P-P, Jaccard IS, Weisz U, Weisz H. International comparison of health care carbon footprints. Environmental Research Letters. 2019. DOI 10.1088/1748-9326/ab19e1
3.Crohn’s and Colitis UK. Epidemiology Summary: Incidence and Prevalence of IBD in the United Kingdom. 2022. Accessed October 10, 2024. https://crohnsandcolitis.org.uk/media/4e5ccomz/epidemiology-summary-final.pdf
4.Rahmany S, Young D, Latter S, Cummings F. P96 Patient benefits of switching from intravenous to subcutaneous infliximab. Gut. 2023;72:A104