Overdiagnosis: harming the healthy

BMAMay 30 2012

Overdiagnosis poses a significant threat to human health by labelling healthy people as sick and wasting resources on unnecessary care, warns Ray Moynihan, Senior Research Fellow at Bond University in Australia, in a feature published on bmj.com today. 

The feature comes as an international conference ‘Preventing Overdiagnosis’ is announced for September 10-12, 2013 in the United States, 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.

The conference is timely, argues Moynihan because “as evidence mounts that we’re harming the healthy, concern about overdiagnosis is giving way to concerted action on how to prevent it.”

“The Dartmouth Institute for Health Policy and Clinical Practice has long been a leader in understanding and communicating the problems of overdiagnosis” say Dr Steven Woloshin and Dr Lisa Schwartz, professors of medicine at The Dartmouth Institute for Health Policy and Clinical Practice. “We are extremely excited to host this international conference to advance the science and develop concrete proposals to reduce overdiagnosis and its associated harms."

Overdiagnosis occurs when people are diagnosed and treated for conditions that will never cause them harm and there’s growing evidence that many people are overdiagnosed and overtreated for a wide range of conditions.

For example, a large Canadian study finds 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 overdiagnosed, and some researchers argue osteoporosis treatments may do more harm than good for women at very low risk of future fracture.

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.

But Moynihan argues that the main problem of overdiagnosis lies in a strong cultural belief in early detection, fed by deep faith in medical technology. “Increasingly we’ve come to regard simply being ‘at risk’ of future disease as being a disease in its own right,” he says.

“It took many years for doctors to accept that bacteria caused peptic ulcers,” says co-author of the BMJ feature, Dr David Henry, Chief Executive Officer 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.”

So what can we do about overdiagnosis?

The 2013 conference will provide a forum for learning more, increasing awareness, and developing ways to prevent the problem. At a policy level, 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 overdiagnosis 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, overdiagnosis is a rapidly growing problem; we must take it seriously now or suffer the consequences of overtreatment and rising health care waste.”

As Moynihan and colleagues write in their BMJ feature, concern about overdiagnosis 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.

Fiona Godlee, Editor-in-Chief at the BMJ said: "The harm of overdiagnosis to individuals and the cost to health systems is becoming ever clearer. Far less clear is what we should do about it. Next year's conference is an important step towards some evidence based solutions."