A reply to: Is the USA’s problem ours too?

This feature article asks if we can relax about ‘needless overtesting, overtreating, and overdiagnosing.’ A principal concern raised is that of screening (1).

‘A stitch in time saves nine’ has long suggested that a timely effort may prevent more trouble later on. This is the mantra behind medical screening: that early diagnosis is a good thing, that it reduces suffering, and that it makes such intuitive sense that there is no need to challenge it.

Gigerenzer in his book Reckoning with risk explores screening and suggests that we consider the ‘illusion of certainty, communication of risk, and how we draw conclusions from numbers’(2).

The benefits of early diagnosis of dementia are well rehearsed, such that we have absolute agreement between medical, political, and third-sector domains. The enthusiasm for this seems to have generated an appetite for the widespread use of (largely unvalidated) cognitive ‘screening’ tests.

For cognitive screening, any certainty needs un-stitching. Forgetfulness is not an inevitable part of ageing, but there is an undeniable association of forgetfulness with age. Here screening over-simplifies, and cannot elucidate a complex set of ill-understood risks that (today) lack robust patho-physiological correlates (even upon death)(3).

What we do know, from epidemiology involving very large numbers (where pharmaceutical trials have found that current medicines are not ‘disease modifying’), is that no more than 50% of our elderly with mild amnesia progress to dementia. It is in this group that we risk a high number of false-positives (4). A diagnosis of ‘Alzheimer’s’ is a life changing diagnosis. Our elderly are generally uncomplaining and may not live long enough to refute such a diagnosis.

It is interesting that Stephen Whitehead, Chief Executive of the Association of the British Pharmaceutical Industry has chosen to respond to this article (5). The Pharmaceutical Industry has been guilty of presenting only the benefits of its products (6). This reflects the current situation with screening where benefits are represented fully but far less the costs.

(1) McCartney, M. Feature: Overtreatment: Is the USA’s problem ours too? BMJ2012;345:e6617

(2) Gigerenzer, G. Reckoning with Risk: Learning to live with uncertainty. Published 2002

(3) Reisa A. Sperlinga et al Toward defining the preclinical stages of Alzheimer’s disease: Recommendations from the National Institute on Aging-Alzheimer’s Association workgroups on diagnostic guidelines for Alzheimer’s disease Alzheimer’s & Dementia 7 (2011) 280–292.

(4) Frances, A. DSM 5 Minor Neurocognitive Disorder. Psychology Today. 16 Feb 2012

(5) Whitehead, S. Rapid response to Overtreatment: Is the USA’s problem ours too? BMJ2012;345:e6617

(6) Goldacre, B. The drugs don’t work. The Guardian Weekly. 5 Oct 2012.

Competing interests: None declared