PA10 Do online clinical trials allow opportunities for efficiencies and reduced carbon footprint of research?

Abstract Our aim was to explore the potential efficiencies of running dermatology clinical trials online. We compared performance efficiencies of two UK eczema clinical trials in terms of (i) speed of recruitment, (ii) retention, (iii) adherence to interventions and (iv) time taken for the results to be publicly available. We also calculated the carbon footprint of the Eczema Bathing Study to better understand the carbon ‘hotspots’ when conducting online clinical trials. Two National Institute for Health and Care Research (NIHR)-funded, pragmatic, randomized controlled trials were compared – the Eczema Bathing Study (citizen science led, online trial, 438 participants, 4 weeks’ duration) and CLOTHES (traditional trial with five recruiting centres, 300 participants, 26 weeks’ duration). The average CO2 emissions generated by NIHR-funded pragmatic trials has been reported to be 78.4 tonnes CO2 equivalent (range 42.1–113). Data for the metrics being compared were sourced from published trial reports, internal documents and interviews with trial staff. Carbon footprinting was completed using guidance from the Low Carbon Clinical Trials Group [Medical Research Council. Greener Trials Team. Available at: https://methodologyhubs.mrc.ac.uk/about/working-groups/trial-conductwg/tcwg-subgroup-greener-trials (last accessed 18 March 2025)]. Activities for carbon footprinting were classified according to the stage of the trial setup, promotion and recruitment; clinical trials unit (CTU) emissions; meetings and travel; data collection; and trial closeout. The online trial demonstrated much faster recruitment (87.6 participants per month vs. 17.7 participants per month), with recruitment to target in just over 5 months compared with 17 months for the traditional trial. The time taken for results to be publicly available was also much faster (29 days vs. 397 days), as the results were released prior to publication in a peer-reviewed academic journal. Retention and adherence were slightly lower for the online trial compared with the traditional trial: retention 88.6% vs. 94.0%, and adherence 73% vs. 84%, respectively. The carbon footprint of the Eczema Bathing Study online trial was 10.5 tonnes CO2 equivalent. The most carbon-intensive activities were trial team commuting and CTU emissions. Activities that could support a reduction in the carbon footprint of clinical trials include completing recruitment quickly, using online meetings, using text rather than paper mailouts, minimizing the impact of commuting, and choosing low-carbon methods of advertising. While direct comparison is difficult, online trials may offer potential for improving the efficiency of clinical trials in situations where remote assessment of outcomes is possible, and advertising direct to potential participants is appropriate. Online trials reduce the carbon footprint by increasing speed of recruitment, and by removing emissions generated by recruiting sites and participant travel. CTU emissions remain the largest factor in determining the carbon emissions of clinical trials. A trial’s carbon footprint should be considered both at the design stage and throughout delivery.