Two members of the Department of Philosophy have shown that using mechanistic studies alongside clinical studies improves evidence-based medicine (EBM). Professor Jon Williamson and Dr Michael Wilde have provided recommendations about how to evaluate mechanistic studies alongside clinical studies. Their recommendations have been taken up by the International Agency for Research on Cancer (IARC) and the National Institute for Health and Care Excellence (NICE).
Clinical studies are used to establish cause and effect, for example that taking opium causes cancer. A common method is that of an observational study. Such a study compares people in a test group and a control group, where the test group is exposed to something that those in the control group are not, such as opium. Researchers then observe any differences between the groups, for example, a difference in the numbers of cancer deaths. This approach can be very effective, but it can also have its limitations – the difference in cancer deaths may not be due to the opium, but some other difference between the test and control group. (There would also be significant ethical problems with this hypothetical example).
Jon and Michael have developed a broader evidential framework called EBM+. They argue that mechanistic studies should be considered alongside clinical studies. Mechanistic studies look at steps on the pathway between cause and effect, between taking opium and developing cancer. Such research asks questions like ‘What happens when you take opium that might cause cancer?’ or ‘Can any key indicators of cancer-causing chemicals be found in the cells of substance users?’ Mechanistic studies thus broaden the available evidence, allowing cancer researchers to make better informed judgements.
IARC has recently adopted insights from EBM+ to improve its methodology for assessing carcinogenicity. As part of the World Health Organization their assessments inform health policies around the globe. Jon and Michael’s research has also led to improvements in the development of NICE guidelines in England and Wales.
‘I believe the work of the EBM+ group is helping us to explore the question around the value and use of different types of evidence (including the use of evidence of mechanisms), from a multi-disciplinary perspective, in order to make practice recommendations that are robust and justifiable. ’ (Beth Shaw, NICE)
NICE is part of the UK Government’s What Works Network, which aims to improve decision making in public policy. Jon and Michael have started to widen their collaborations with this network. They are currently working with Virginia Ghiara at the Early Intervention Foundation on a joint project to identify new ways of evidencing through the application of EBM+.