Environmental sustainability considerations in the reporting of randomised clinical trials

Randomised clinical trials (RCTs) can contribute substantially to carbon dioxide emissions. In this Viewpoint, we explored the extent to which primary publications of RCTs reported environmental sustainability considerations in their study design (eg, resource use and travel movement) and outcomes (eg, the environmental impact of interventions under study). 252 RCTs published between Oct 17, 2022, and Oct 17, 2023, in five prominent medical journals, The Lancet, TheNew England Journal of Medicine, Nature Medicine, TheBritish Medical Journal, and PLOS Medicine, were included. Sustainability-related statements were reported in 29 (12%) of 252 of RCTs, but only four (1·6%) of 252 explicitly referenced sustainability considerations in their study design or outcome. Thus, environmental sustainability aspects of the study design decisions or outcomes collected seem to be rarely reported in primary publications of RCTs. The findings of this Viewpoint highlight the need for strategies for improved awareness of reporting of environmental sustainability considerations in the context of RCTs.