Carbon cost of pragmatic randomised controlled trials: retrospective analysis of sample of trials
BMJ 2009; 339 doi: https://doi.org/10.1136/bmj.b4187 (Published 30 October 2009) Cite this as: BMJ 2009;339:b4187
- Katy Lyle, research fellow1,
- Louise Dent, acting principal research fellow1,
- Sally Bailey, senior programme manager1,
- Lynn Kerridge, chief executive officer1,
- Ian Roberts, professor of epidemiology and public health2,
- Ruairidh Milne, director of strategy and development1
- 1NIHR Evaluation, Trials and Studies Coordinating Centre, University of Southampton, Southampton SO16 7NS
- 2London School of Hygiene and Tropical Medicine, London WC1E 7HT
- Correspondence to: K Lyle k.lyle{at}southamtpon.ac.uk
- Accepted 1 September 2009
Abstract
Objective To calculate the global warming potential, in carbon dioxide (CO2) equivalent emissions, from a sample of pragmatic randomised controlled trials.
Design Retrospective analysis.
Data source Internal data held by NIHR Evaluation, Trials and Studies Coordinating Centre.
Studies included All eligible pragmatic randomised controlled trials funded by the NIHR Health Technology Assessment programme during 2002 and 2003.
Main outcome measure CO2 equivalents for trial activities calculated with standard conversion factors.
Results 12 pragmatic randomised controlled trials involving more than 4800 participants and a wide range of technologies were included. The average CO2 emission generated by the trials was 78.4 (range 42.1-112.7) tonnes. This is equivalent to that produced in one year by approximately nine people in the United Kingdom. Commuting to work by the trial team generated the most emissions (average 21 (11.5-35.0) tonnes per trial), followed by study centres’ fuel use (18 (9.3-32.2) tonnes per trial), trial team related travel (15 (2.0-29.0) tonnes per trial), and participant related travel (13 (0-46.7) tonnes per trial).
Conclusions CO2 emissions from pragmatic randomised controlled trials are generated in areas where steps could be taken to reduce them. A large proportion of the CO2 emissions come from travel related to various aspects of a trial. The results of this research are likely to underestimate the total CO2 emissions associated with the trials studied, because of the sources of information available. Further research is needed to explore the additional CO2 emissions generated by clinical trials, over and above those generated by routine care. The results from this project will feed into NIHR guidelines that will advise researchers on how to reduce CO2 emissions.
Footnotes
We thank the following people for their hard work in collecting data for the project: Syd Anstee, Lisa Douet, Marina Malaffo, Claire Rosten, and Tannaze Tinnati. We also thank David Pencheon for his advice and support.
Contributors: KL and LD were involved in all stages of the study. SB assisted with data collection and was a member of the steering group. LK and IR contributed to the design of the project through their involvement in the steering group. RM was a member of the steering group and was involved in revising the article critically and approving it for publication. All authors critically reviewed and agreed the final draft. KL and LD are the guarantors.
Funding statement: This study was carried out by NIHR Evaluations Trials and Studies Coordinating Centre (NETSCC), which manages the Health Technology Assessment programme. KL, LD, SB, LK, and RM are employed by NETSCC. No additional funding was sought for this research
Competing interests: None declared.
Ethical approval: Not needed.
Data sharing: No additional data available.
- Accepted 1 September 2009
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