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
All rapid responses
Rapid responses are electronic comments to the editor. They enable our users to debate issues raised in articles published on bmj.com. A rapid response is first posted online. If you need the URL (web address) of an individual response, simply click on the response headline and copy the URL from the browser window. A proportion of responses will, after editing, be published online and in the print journal as letters, which are indexed in PubMed. Rapid responses are not indexed in PubMed and they are not journal articles. The BMJ reserves the right to remove responses which are being wilfully misrepresented as published articles or when it is brought to our attention that a response spreads misinformation.
From March 2022, the word limit for rapid responses will be 600 words not including references and author details. We will no longer post responses that exceed this limit.
The word limit for letters selected from posted responses remains 300 words.
Lyle et al. (1) estimate that the average CO2 emission of randomised
trials is 78.4 tonnes. This carbon cost occurs whether or not a trial is
published. Every year an estimated 12,000 trials which should have been
fully reported are not (2, 3). Hence under-reporting of trials wastes just
under a million tonnes of carbon dioxide annually (the equivalent of
carbon emissions from about 800,000 round trip flights between London and
New York). This environmental cost of under-reporting of research is in
addition to its scientific and ethical costs: biased under-reporting of
research has resulted in the avoidable suffering and deaths of patients.
More than a decade ago, the Faculty of Pharmaceutical Medicine
declared that under-reporting of research is incompatible with good
scientific practice and with the duties of doctors to patients (4). As far
as we are aware, the Faculty remains the only professional representative
body in the UK to have published statements of principle on this issue.
Specifically, appeals to the Academy of Medical Sciences, the Royal
College of Physicians of London, and the Royal Statistical Society have so
far failed to lead to any endorsements of the principled position adopted
by the Faculty of Pharmaceutical Medicine.
Non-publication may occur for several reasons, but there is now
substantial evidence that the vested interests of commercial sponsors and
their professional collaborators predisposes to biased under-reporting of
research. While further research might help to elucidate other reasons
for non-publication, our incomplete understanding of the reasons for under
-reporting of research is not a reason for leaving doubt about whether
professionals are concerned about the phenomenon. We strongly suggest all
professional representative organisations follow the longstanding lead of
the Faculty of Pharmaceutical Medicine and take steps to reduce under-
reporting of research. As long as they fail to do this, the public will
be justified in concluding that professionals rate the interests of
patients as less important than commercial and professional interests.
References
1 Lyle K, Dent L, Bailey S, Kerridge L, Roberts R, Milne R. Carbon
cost of pragmatic randomised controlled trials: retrospective analysis of
sample of trials. BMJ 2009;339:b4187.
2 Chalmers I, Glasziou P. Avoidable waste in the production and
reporting of research evidence. Lancet 2009;374:86-89. doi:10.1016/S0140-
6736(09)60329-9.
3 Bastian H, Glasziou P, Chalmers I. Seventy-five trials and eleven
systematic reviews a day: How will we ever cope? PLoS Medicine (in press).
4 Faculty of Pharmaceutical Medicine. Ethical Issues Working Group.
Ethics in pharmaceutical medicine. International Journal of Pharmaceutical
Medicine 1998;12:193-8.
Competing interests:
None declared
Competing interests: No competing interests
At what cost evidence synthesis? A rapid response to Lyle et al. (2009) “Carbon cost of pragmatic randomised controlled trials: retrospective analysis of sample of trials”
The carbon cost of conducting randomised controlled trials, estimated
by Lyle et al (1) highlights the need to ensure that existing research is
used to the full. As discussed by Chalmers & Glasziou (2), a number of
questions of importance to clinicians and patients could potentially be
answered using existing evidence. Adopting such an approach may help
reduce carbon emissions associated with the production of research
evidence.
Based on the methods reported by Lyle et al., we have estimated the
carbon footprint of 14 evidence synthesis projects currently ongoing
within the National Institute for Health Research, Health Technology
Assessment (NIHR, HTA) programme portfolio. Data were taken from research
management records held at NETSCC. Data were collected on the number of
full-time equivalent staff on the project, IT equipment procured for the
project and any national and/or international travel undertaken by the
project team. It was assumed that, as the projects were evidence synthesis
studies (including systematic reviews and economic modelling studies),
work would be ‘desk-based’. CO2 emissions were calculated for energy use
at study centres, for staff commuting to and from the study centres and
for additional national and international travel to meetings and
conferences.
Results from this analysis are reported in Table 1. We estimate that
the average CO2 emission generated by an evidence synthesis project is
10.06 tonnes, 12.8 % that of a clinical trial and the equivalent saving of
taking 27 cars off the road. From an environmental perspective, our
findings support the argument that new clinical trials should not be
undertaken without fully exploiting existing evidence.
References
1 Lyle K, Dent L, Bailey S, Kerridge L, Roberts R, Milne R. Carbon
cost of pragmatic randomised controlled trials: retrospective analysis of
sample of trials. BMJ 2009;339:b4187.
2 Chalmers I, Glasziou P. Avoidable waste in the production and
reporting of research evidence. Lancet 2009;374:86-89. doi:10.1016/S0140-
6736(09)60329-9.
Competing interests:
None declared
Table 1: CO2 emissions estimated for evidence synthesis projects
Competing interests: Number Study type Total cost (£) Total CO2 (tonnes) CO2 per year (tonnes) CO2 per £ spent (kg) CO2 per WTE staff (tonnes)1 Systematic review 143,150 7.23 4.82 0.050 7.232 Systematic review 258,234 8.77 5.85 0.034 3.643 Systematic review 106,655 6.34 6.34 0.059 3.734 Evidence synthesis 181,039 7.48 6.41 0.041 3.175 Evidence synthesis 277,203 10.57 5.29 0.038 6.616 Evidence synthesis 111,572 6.32 6.32 0.057 2.447 Evidence synthesis 281,013 33.02 22.01 0.118 15.158 Evidence synthesis 161,065 6.38 5.89 0.040 3.169 Evidence synthesis 178,793 6.13 6.13 0.034 3.4110 Systematic review 244,441 8.15 5.43 0.033 3.5411 Systematic review 91,015 2.85 2.85 0.031 2.6112 Systematic review 200,276 12.20 12.20 0.061 5.2813 Evidence synthesis 237,747 20.97 10.49 0.088 6.6614 Evidence synthesis 159,652 4.37 3.50 0.027 3.47 Average 187,990 10.06 7.39 0.051 5.01