You might have heard the frightening news last year suggesting half of all Americans had some form of diabetes. A survey in the journal JAMA was covered extensively, including by NBC, WebMD and the Los Angeles Times.

But as the HealthNewsReview blog later pointed out, almost none of the media coverage raised questions about the expanding definition of diabetes or the controversial new “pre-diabetes”, claimed to afflict close to 90 million Americans.

Part of the expanding empires of disease, the creation of new “pre-conditions” is turning millions of people into patients across the globe. We now have pre-osteoporosis, pre-hypertension and pre-dementia – and, like pre-diabetes, all of them are controversial.

An article in The BMJ (British Medical Journal) in 2014 asked bluntly “whether it is worth having the category of pre-diabetes at all”. It suggested the term go into cold storage until it was clear that the millions of people being labelled with it would actually benefit.

“Rather than turning healthy people into patients with pre-diabetes,” argued two distinguished professors in The BMJ, “we should use available resources to change the food, education, health and economic policies that have driven this epidemic.”

Diagnosis creep

As I explain in an editorial on this problem of “diagnosis creep” in the journal Australian Prescriber today, there is an urgent need for much greater scepticism about the expanding empires of disease – and we’re not just talking about pre-diseases.

A dramatically expanded definition of “chronic kidney disease” gives a label to around one in ten adults, and almost half of the elderly, many of whom will never suffer any kidney disease, chronic or otherwise.

New diagnostic criteria will almost triple the numbers of pregnant women who are labelled as having gestational diabetes – without good evidence that the newly labelled women or their babies will benefit.

And thresholds that define attention-deficit hyperactivity disorder (ADHD) continue to fall, which means even more children and now adults will be diagnosed.

Early diagnosis is a double-edged sword

Medicine is transforming more and more formerly healthy people into patients and building ever bigger potential markets for the industries that sell treatments.

Some of the newly labelled patients will benefit – early detection can mean deadly disease is stopped in its tracks.

But early diagnosis is a double-edged sword. For other people with mild problems or at very low risk of future illness, a diagnosis can bring more harm than good. It can cause a cascade of overtesting and overtreatment and waste precious resources better spent on those in greatest need.

A few years ago, colleagues and I analysed changes made by expert panels of doctors to the definitions of 14 common conditions, including high-blood pressure, depression, arthritis and Alzheimer’s disease. Our study was published in the international journal PLOS Medicine and was covered on The Conversation.

In summary, most conditions were expanded – including high blood pressure, Alzheimer’s disease, high cholesterol, depression, rheumatoid arthritis, multiple sclerosis and myocardial infarction or heart attack. Pre-diseases were created, thresholds for diagnosis were lowered, or the processes used to diagnose were changed so that people would be diagnosed and labelled earlier.

No panel rigorously investigated and reported on the potential downside of their decision to expand – the danger that some people might be caught unnecessarily by the newly widened definitions.

No panels reported on the possibility that the new patients created by the new definitions might be “overdiagnosed” – they might be labelled with a disease that would never harm them, or be given a diagnosis and treatment that would do them more harm than good.

An epidemic of conflicts of interest

Perhaps most disturbingly, among the panels of experts who included disclosure sections in their publications, 75% revealed multiple financial ties to around seven drug companies each.

These influential doctors – who were deciding whether millions of people around the world would be defined as healthy or sick – were being paid directly by pharmaceutical companies for activities like speaking, consulting, advising or researching.

This epidemic of conflicts of interest is in direct contrast to recommendations from organisations like the prestigious US Institute of Medicine, which is calling for much greater independence among those who write influential medical guidelines.

Some of the conflicts are unbelievable. Among the expert guideline panel that in 2003 created a diagnostic category called “pre-hypertension” or pre-high blood pressure, 80% of members disclosed ties to an average of around 12 companies each, including companies selling drugs for high blood pressure.

More than half of the members of the 2011 panel that described “pre-dementia” and defined “pre-clinical” Alzheimer’s disease had financial ties to around five companies each.

It was a similar situation for the 2012 psychiatric panels that widened the definitions of depression and attention-deficit hyperactivity disorder. More than half of the experts disclosed links to drug companies, including those that could directly benefit by selling drugs to expanded patient populations.

Reforming unhealthy disease definitions

There is a growing unease about these expanding empires of disease and the epidemics of conflicts of interest among those driving the expansion.

A series in The BMJ is examining expanding disease definitions and the risk of overdiagnosis. It has already included articles on the controversy over gestational diabetes, attention-deficit hyperactivity disorder, chronic kidney disease, pre-dementia, mild hypertension, osteoporosis and pulmonary embolism.

A group of GPs in the UK have successfully lobbied the Royal College of General Practitioners to set up a standing committee to address overdiagnosis. Some of them last month called for a “grassroots revolution” to tackle this problem.

Across Europe, the new “quaternary prevention” movement is also gathering strength. This doctor-led movement is aimed at preventing people receiving diagnoses that may do them more harm than good.

Globally, the Guidelines International Network – an umbrella group for all medical guidelines – has just created an overdiagnosis working group to push the process of reform.

At the same time, many global initiatives are addressing the problem of too much medicine, including Choosing Wisely, The Right Care campaign and the international Preventing Overdiagnosis conferences, the fourth being held in Barcelona this September.

But until we see genuine reform of the conflicted panels that define diseases – greater independence, more broadly representative and much more interested in both the benefits and harms of their decisions – a healthy scepticism about expanding definitions is highly recommended.

This ideas in this article are based on a piece published today in the peer-reviewed journal Australian Prescriber.