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Preventing over-diagnosis: how to stop harming the healthy

Over-diagnosis happens when people are diagnosed with diseases or conditions that won’t actually harm them.

OVER-DIAGNOSIS EPIDEMIC – In the first instalment of a nine-part series Ray Moynihan outlines the growing problem of over-diagnosis.

If you haven’t heard much yet about the problem of over-diagnosis, rest assured you soon will. In recent weeks, an editorial in a leading medical journal in the United States has dubbed over-diagnosis a “modern epidemic”; in Britain the BBC has just broadcast a two-part investigative series on it; and today this website kicks off a two-week long exploration of the problem.

To put it simply, over-diagnosis happens when people are diagnosed with diseases or conditions that won’t actually harm them. It happens because some screening programs can detect “cancers” that will never kill, because sophisticated diagnostic technologies pick up “abnormalities” that will remain benign, and because we are routinely widening the definitions of disease to include people with milder symptoms, and those at very low risk.

A growing problem

There’s a small but growing scientific literature on the problem of over-diagnosis across many different conditions, from ADHD to malaria. Some of the strongest evidence comes from the world of breast cancer, with suggestions from a recent systematic review that up to one in three women diagnosed through mammography screening may, in fact, be “over-diagnosed”. In other words, their cancer may not kill them.

There are varying estimates, and the evidence is still being gathered, but as you will learn from tomorrow’s article, the problem of over-diagnosis of breast cancer demands much greater attention.

Josh Kenzer

Another powerful example is the condition known as pulmonary embolism – blood clots that can cause heart attacks and death. The problem here is that technology is increasingly allowing us to see smaller and smaller clots, leading to a big increase in the numbers of people being diagnosed and treated.

As researchers start to investigate the problem of over-diagnosis, they’re finding growing evidence that many people may be being diagnosed and treated unnecessarily. As that editorial in the Archives of Internal Medicine said, “Pulmonary embolism is a model for the modern phenomenon of overdiagnosis.” (Sadly, this editorial is behind a paywall – Ed.)

At the same time, ever-widening definitions of disease are catching increasing numbers of healthy people in the net of illness, particularly with the fashion now for creating “pre-diseases”. Pre-hypertension – created as a new diagnostic category in 2003 – is highly controversial, with some senior figures rejecting it as a pseudo-syndrome designed to expand the market for drugs.

There are similar controversies around “pre-diabetes” and “pre-osteoporosis”, arbitrary labels that expose tens of millions of people to powerful, costly and sometimes lifelong treatments that may do them more harm than good.

But why?

The problem of over-diagnosis may well have resulted from the best of intentions – too much of a good thing. The idea of early diagnosis, of getting in and nipping things in the bud, makes intuitive sense, but we are increasingly realising it’s a double-edged sword.

Not everyone with the early signs of a disease, or at risk of future illness, will actually go on to develop it. Treating essentially healthy people as if they were sick may not only cause them harm, but can also pull precious resources from those who can actually benefit from diagnosis and treatment.

As my co-authors and I outlined in an article in the British Medical Journal (BMJ) earlier this year, the drivers of this phenomenon are complex and multifaceted. These include professional and commercial self-interest; litigation fears; our cultural love affairs with early diagnosis and the wonders of technology; and the nature of the health system itself, where a fee-for-service system brings benefits for doing more tests, more treatments, more procedures. But research evidence is starting to suggest that, in many situations, less may be more.

Swallowing pills from Shutterstock

In April this year, folks at Bond University’s Centre for Research in Evidence-Based Practice hosted a small gathering on over-diagnosis. The participants decided to organise a bigger international meeting to be held exactly a year from today (10th to 12th September, 2013), at the Dartmouth Institute for Health Policy and Clinical Practice, in Hanover New Hampshire in the United States.

Dartmouth is a natural home for the conference, not least because of a powerful book by three of its academics last year, Overdiagnosed: Making People Sick in the Pursuit of Health. It’s an accessible, rigorous and scholarly work on the topic, which is highly recommended.

In partnership with the BMJ and leading US consumer organisation Consumer Reports, the conference is designed to bring together research and researchers from around the world to talk about how to improve methods, enhance communication, and develop policy responses to the problem. Click here to learn more about the conference.

Over the next two weeks The Conversation will be running a timely and informative series of articles about different aspects of over-diagnosis – a topic of growing interest to professionals, the public and policy-makers. This a great opportunity to work together to try and deepen our understanding of the problem, and develop solutions to it.

A special thanks to Ray Moynihan for his assistance with this series – Ed.

Have you or someone you know been over-diagnosed? To share your story, email the series editor.

This is part one of our series on over-diagnosis, click on the links below to read other articles:

Part two: Over-diagnosis and breast cancer screening: a case study

Part three: The perils of pre-diseases: forgetfulness, mild cognitive impairment and pre-dementia

Part four: How genetic testing is swelling the ranks of the ‘worried well’

Part five: PSA screening and prostate cancer over-diagnosis

Part six: Over-diagnosis: the view from inside primary care

Part seven: Moving the diagnostic goalposts: medicalising ADHD

Part eight: The ethics of over-diagnosis: risk and responsibility in medicine

Part nine: Ending over-diagnosis: how to help without harming

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