Screening Frenzy, UK

Main Category: Public Health
Article Date: 13 Dec 2007 - 4:00 PDT

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Screening expert calls for public to be protected from over-zealous promotion of medical screening.

A leading epidemiologist and preventive health expert has criticised over-zealous promotion of health screening services by insurance companies and other commercial concerns who offer tests of dubious benefit and possible harm. Professor Nicholas Wald argues that there needs to be a Medical Screening Code of Practice to protect the public.

"Contrary to popular belief, screening is usually a weak means of providing reassurance because screening generally misses most cases of the disease for which screening is carried out."

Writing in the December issue of the Journal of Medical Screening - of which he is the Editor - Professor Wald questions the promotion, often by insurance companies, for screening tests which have no real benefit and which may even be harmful. "There is, emerging in Britain, a culture in which judgements on medical screening practice are being made in the absence of evidence….The culture needs to change, so that screening is subject to professional scientific assessment."

Professor Wald, who is also Director of the Wolfson Institute of Preventive Medicine and President of the Medical Screening Society, points out that the examinations and tests offered by, for example, Saga Insurance in their Saga MultiScan*, have not been shown to be worthwhile.

The author cautions that, as yet, there have not been enough trials to show that either computerised tomography (CT) scanning of the heart, nor virtual (CT) colonoscopy, are of benefit, and the X-ray radiation exposure involved in both procedures is a concern, as described in a paper by Amy Berrington in the same issue of the Journal.

Bone density and cholesterol levels are important factors in the causation of osteoporosic fractures and ischaemic heart disease respectively. This may have led people to believe that they would also be good screening tests, but they are not; within a population they are poor discriminators of who will develop these disorders and who will not. Whether screening for diabetes is worthwhile is also still uncertain.

In referring to screening using CT scanning, Professor Wald writes: "Not only do we lack evidence that this sort of screening confers a benefit, we do know that it will also cause harm." This is not just from the radiation risk of some imaging techniques - other techniques can carry a risk of physical harm. Also anxiety over the risk of false positives and the false reassurance of false negatives is a concern. "In medical screening there is always some harm, which is only acceptable if there are also confirmed benefits that outweigh the harm."

Professor Wald believes that if government regulation is to be avoided, health service providers, insurers and scientists need to work together to produce a Medical Screening Code of Practice. Such a code would help to reassure the public and better enable them to judge the value and benefit of screening services.

Screening: a step too far. A matter of concern

Notes:

There is a related article in the current issue of the BMJ.

* Saga have a page entitled "Are there any risks associated with having a scan?" available on http://www.saga.co.uk/healthscreening/risks.asp.

The Saga product is provided by Lifescan Ltd.

Professor Nicholas Wald is the Director of the Wolfson Institute of Preventive Medicine at Bart's and The London School of Medicine and Dentistry in the University of London. He is the editor of the Journal of Medical Screening and is President of the Medical Screening Society. His main research interests are medical screening (particularly antenatal and cancer screening) and epidemiology, including the etiology and prevention of birth defects (such as neural tube defects), cancer and cardiovascular disease.

The Journal of Medical Screening is published by RSM Press, the publishing arm of the Royal Society Of Medicine. The Journal is concerned with all aspects of medical screening, particularly the publication of research that advances screening theory and practice. It aims to increase awareness of the principles of screening (quantitative and statistical aspects), screening techniques and procedures and methodologies from all specialties.

Royal Society Of Medicine