The term, rejected as diagnosis by World Health Organization, is still used in the UK and US

Labelling people as having pre-diabetes could do more harm than good, experts have said, as research reveals that even some of those involved in coining the term now reject it.

The American Diabetes Association (ADA) introduced the term “pre-diabetes” at the turn of the millennium. It is used to describe someone at risk of developing diabetes but who does not have the disease or symptoms, and is based on a measure of average blood glucose concentration.

Critics, however, say the threshold the ADA sets for such levels makes patients out of healthy people. They say it has not only led to huge sums of public money being spent on ineffective interventions, but has also fuelled moves by the pharmaceutical industry and diet and fitness professionals to target so-called pre-diabetics. They also say only a small proportion of those labelled as pre-diabetic go on to develop diabetes, while such a diagnosis causes unnecessary worry and problems with health insurance and employment.

The World Health Organization has rejected pre-diabetes as a diagnosis, but it is still widely used, particularly in the US where Centers for Disease Control and Prevention (CDC) has adopted the ADA definition.

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An investigation published in the Science journal reveals that some of those involved in promoting the term have staunchly defended it and the ADA definition, but others – including Richard Kahn, the ADA’s former chief scientific and medical officer who helped to coin it – has rejected it.

“Given the avalanche of questionable spending and the wave of anxiety it has unleashed, Kahn now says he rues the day he helped promote the term pre-diabetes, calling it ‘a big mistake,’” writes Charles Piller, the author of the report.

The research highlights the fact that the ADA not only continues to use the term but in 2010 lowered the average blood glucose concentration required to label someone as pre-diabetic. The move went against the decision by other expert organisations, including the International Diabetes Federation, to reject the term pre-diabetes and set a higher threshold trigger preventive action.

Both the ADA and CDC continue to promote the idea that pre-diabetes is a grave health problem, the report states, and the ADA has begun to back the use of drugs in those that meet its criteria. Piller, however, reveals concerns about financial conflicts of interest, with the ADA receiving money from drug companies. He also points out that many of the medicines prescribed to pre-diabetics have serious side effects.

He says the CDC and ADA have rebuffed criticisms by pointing to studies that suggest lifestyle changes and possibly drugs could help to prevent pre-diabetes progressing to diabetes – studies Piller notes are controversial.

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It is not the first time that pre-diabetes has been criticised. Scientists spoke out against it in 2o14, when they said most individuals labelled with the condition did not go on to develop diabetes and that there was no evidence that treating them with drugs would bring benefits.

Figures suggest a third of adults in the UK or about 16 million people qualify as pre-diabetic under the ADA criteria, while only about 3.3 million have been diagnosed with type 2 diabetes.

Prof Andrew Hattersley, a diabetes expert at the University of Exeter, said the issue was a matter of definition. “It is not a ridiculous concept to identify people who are close to having diabetes. People just below the threshold will benefit from the lifestyle advice given to those just above the threshold,” he said.

He added, however, that the scientific evidence for ADA’s low thresholds is very weak, and that broadening the definition to such a degree means huge numbers of people with very little increased risk will be classed as pre-diabetic.

He also said that interventions are often less than effective. “Potentially the most effective way to reduce the development of diabetes would be to push for changes in food regulations, taxation and town planning to try to mitigate the obesogenic environment in which we all live,” he said.