Teleoanalysis: combining data from different types of studyBMJ 2003; 327 doi: http://dx.doi.org/10.1136/bmj.327.7415.616 (Published 11 September 2003) Cite this as: BMJ 2003;327:616
- Nicholas J Wald, professor (firstname.lastname@example.org)1,
- Joan K Morris, senior lecturer1
- 1 Wolfson Institute of Preventive Medicine, Barts and the London, Queen Mary's School of Medicine and Dentistry, University of London, London EC1M 6BQ
- Correspondence to: N Wald
- Accepted 9 July 2003
Teleoanalysis can provide the answer to questions that would be obtained from studies that have not been done and often, for ethical and financial reasons, could never be done
Once a causal link has been established between a risk factor and a disease it is often difficult, and sometimes impossible, to determine directly the dose-response relation. For example, although we know that saturated fat intake increases the risk of ischaemic heart disease, the exact size of the effect cannot be established experimentally because long term trials of major dietary changes are impractical. One way to overcome the problem is to produce a summary estimate of the size of the relation by combining data from different types of study using an underused method that we call teleoanalysis. This summary estimate can be used to determine the extent to which the disease can be prevented and thus the most effective means of prevention. We describe the basis of teleoanalysis, suggest a simple one-step approach, and validate the results with a worked example.
What is teleoanalysis?
Teleoanalysis can be defined as the synthesis of different categories of evidence to obtain a quantitative general summary of (a) the relation between a cause of a disease and the risk of the disease and (b) the extent to which the disease can be prevented. Teleoanalysis is different from meta-analysis because it relies on combining data from different classes of evidence rather than one type of study.
Randomised trials with disease end points are often not enough to determine dose-response relations; their results tend to be limited by factors such as dose, duration of treatment, and a limited age range of subjects. We also need data from observational epidemiological studies (particularly large cohort studies) and often knowledge of the mechanism of action. Short term trials using drugs or vitamins are …