Overdiagnosis poses significant threat to human health

The feature comes as an international conference ʻPreventing Overdiagnosisʼ is announced for Sept. 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 organization Consumer Reports and Bond University, Australia.

The conference is timely, says Moynihan because "as evidence mounts that weʼre 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 Drs. Steven Woloshin and 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 thereʼs growing evidence that this occurs 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 breast cancers detected through screenings 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, Professors Jenny Doust and 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 weʼve come to regard simply being ʻat riskʼ 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 recognize 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 from the incentives that tend to reward overdiagnosis.

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.