Over-diagnosis poses a significant threat to human health by labelling healthy people as sick and treating them for conditions that will never do them any harm so wasting resources on unnecessary care.
Ray Moynihan, Senior Research Fellow at Bond University in Australia, writing in bmj.com today argues that the main problem of over-diagnosis lies in a strong cultural belief in early detection, fed by deep faith in medical technology.
He cites the examples of a large Canadian study which found that almost a third of people diagnosed with asthma may not have the condition, a systematic review suggests up to one in three screening detected breast cancers may be over-diagnosed, and some researchers who argue osteoporosis treatments may do more harm than good for women at very low risk of future fracture.
“Increasingly we’ve come to regard simply being ‘at risk’ of future disease as being a disease in its own right,” he says. “As evidence mounts that we’re harming the healthy, concern about over-diagnosis is giving way to concerted action on how to prevent it.”
Many factors are driving overdiagnosis, including commercial and professional vested interests, legal incentives and cultural issues, say Moynihan and co-authors, Professor Jenny Doust and Professor David Henry.
Ever-more sensitive tests are detecting tiny “abnormalities” that will never progress, while widening disease definitions and lowering treatment thresholds mean people at ever lower risks receive permanent medical labels and life-long therapies that will fail to benefit many of them.
Added to this, is the cost of wasted resources that could be better used to prevent and treat genuine illness.
“It took many years for doctors to accept that bacteria caused peptic ulcers,” says, Dr Henry, the chief executive of the Institute for Clinical Evaluative Sciences, and Professor in the Department of Medicine at the University of Toronto, Canada. “Likewise, it will be hard for doctors and the public to recognise that the earliest detection of disease is not always in the best interests of patients.”
At a policy level, the authors say there is a clear need for more independent disease definition processes free from financial conflicts of interest, and a change to the incentives that tend to reward over-diagnosis is also required.
A leading global authority on evidence-based practice, Professor Paul Glasziou, from Bond University in Australia says: “As a side effect of our improving diagnostic technology, over-diagnosis is a rapidly growing problem; we must take it seriously now or suffer the consequences of over-treatment and rising health care waste.”
As Moynihan and colleagues add that concern about over-diagnosis in no way precludes awareness that many people miss out on much needed healthcare. On the contrary, resources wasted on unnecessary care can be much better spent treating and preventing genuine illness, not pseudo-disease. “The challenge is to work out which is which, and to produce and disseminate evidence to help us all make more informed decisions about when a diagnosis might do us more harm than good,” they conclude.
A major conference on identifying and tackling over-diagnosis has been announced for September next year hosted by The Dartmouth Institute for Health Policy and Clinical Practice, in partnership with the BMJ, the leading consumer organisation Consumer Reports and Bond University, Australia.