Article questions the validity of labelling and treating people with ‘pre-diabetes’

Type 2 diabetes is a condition characterised by raised levels of glucose in the bloodstream, and its diagnosis is generally made when blood glucose levels are higher than 11.1 mmol/l (200 mg/dL) 2 hours after a oral glucose load (of 75 g).

However, blood sugar control is a spectrum: between what are thought to be ‘healthy’ blood sugar levels and type 2 diabetes exist states which are not extreme enough to be called diabetes, but are associated with enhanced risk of developing this condition.

For example, if the glucose concentration 2 hours after the glucose load is 7.8-11.1 mmol/L (140-200 mg/dL), then a diagnosis of ‘impaired glucose tolerance’ is made. The term ‘Impaired fasting glucose’ is also used to define individuals with fasting blood glucose levels of 6.1-6.9 mmol/L (110-125 mg/dL) (according to the World Health Organization).

Another relatively newly-coined term is ‘pre-diabetes’. This diagnosis is based on a measurement known as the HbA1c which gives an indication of the overall blood sugar (glyaemic) control over the preceding 3 months or so. One of the supposed advangates of this test is that it does not require fasting nor an oral glucose load. According to the American Diabetes Association, a HbA1c of 5.7%-6.4% indicates ‘pre-diabetes’, though some bodies have recommended a slightly higher threshold for this condition. The basic thinking here is that by identifying pre-diabetes, individuals may be helped with interventions including drug therapy.

While this all may seem eminently sensible on the surface, there are a number of problems with this approach. These are explored in quite some detail in a paper published this week in the British Medical Journal co-authored by Professor John Yudkin from University College London and Professor Victor Montori from the Mayo Clinic in the US [1].

The article explains that the relationship between glycaemic control and health risks are a continuum, and where we begin to diagnose pre-diabetes is utterly arbitrary. If we apply the criterion recommended by the ADA, then apparently half the Chinese population (that’s almost half a billion people) have pre-diabetes. The authors question whether we even have the resources to treat vast swathes of the population according to these arbitrary criteria.

Of course a stronger case might be made for those arguing for population treatment if this had been tested. But as the authors point out, there simply is no evidence that earlier intervention based on the ADA’s criteria leads to either improved health or a reduced risk of death.

What we do know if that certain interventions appear to be able to delay the onset of diabetes by about 2-4 years. The real effects in terms of reducing healthcare costs or disease burden, though, are unknown.

And even if genuine benefits exist, let’s not forget that applying a diagnosis of ‘pre-diabetes’ to someone is not without risk. We have risks associated with medication, say, but also there may be issues with self-image, health and life insurance (particularly in the US).

One of the first-line drugs used to treat pre-diabetes is metformin. The authors point out that data suggest that using this drug may reduce the risk of developing type 2 diabetes by about 31 per cent. However, as the authors point out, what this means is that treating pre-diabetes in this way means individuals now have a “100% chance of using metformin with the goal of reducing by 31 per cent their risk of developing a condition that might require them to use metformin.”

This approach with metformin or some other drug may have some sections of the drug industry rubbing their hands with glee, I suppose, but it’s certainly true that overall benefit is not assured, and there is even considerable potential for harm.

The authors are sceptical regarding any supposed benefits, and also warn that we risk deflecting from the real issues with diabetes and pre-diabetes relating, for instance, to diet and exercise. The article ends with three points that doctors should discuss with patients. These are:

  • A diagnosis of pre-diabetes does not mean that you will develop diabetes. In fact, of 100 people like you, fewer than 50 are likely to develop diabetes in the next 10 years
  • There are ways of reducing your risk of developing diabetes that involve changing your diet and being active. These can result from efforts you make as well as changes in your environment (food supply, workplace conditions, education, and other social determinants of health)
  • There are drugs to delay diabetes, but these are the same drugs you will need if you do develop diabetes, and the value of starting them before you have developed diabetes is unknown

The footnotes to the article state that: “The authors are clinical academics with a shared interest in patient centred diabetes care and shared decision making.” And this comes loud and clear in their article, I think. Their focus really does seem to be on taking an objective look at the data and giving patients the very best information on which a truly informed decision can be made.

The article also states that it is: “…part of a series on overdiagnosis looking at the risks and harms to patients of expanding definitions of disease and increasing use of new diagnostic technologies. The underlying message here is that more medicine is not necessarily better (and may in fact be a bad thing). We need more articles like this, and we need more high profile medical journals willing to publish them.


1. Yudkin JS, et al. The epidemic of pre-diabetes: the medicine and the politics. BMJ 2014;349:g4485

29 Responses to Article questions the validity of labelling and treating people with ‘pre-diabetes’

  1. Jake 18 July 2014 at 2:58 pm #

    Prediabetes indentifcation would be valuable if doctors would tell the patients, ” you are carb sensitive, you must restrict your consumption of carbs front now on.”

    Of course, very few doctors tell their patients that, so the Prediabetes designation is worthless.

    • Jennifer 19 July 2014 at 2:42 am #

      .So true Jason,
      Drs suggestions to lower carbs and exercise probably would be ignored, sadly,

  2. Susan 18 July 2014 at 5:12 pm #

    The article also states that it is: “…part of a series on overdiagnosis looking at the risks and harms to patients of expanding definitions of disease and increasing use of new diagnostic technologies. The underlying message here is that more medicine is not necessarily better (and may in fact be a bad thing). We need more articles like this, and we need more high profile medical journals willing to publish them.

    To which, I can only say, “Amen!”

    • M. Cawdery 19 July 2014 at 9:49 am #

      If you are interested in risk and its proper assessment you might like to view

      Prof.Gerd Gigerenzer has also written a book “Risk Savvy” where he looks at risk assessment in commerce, banks, medicine etc. Eye opening and well worth reading!

  3. Frederica Huxley 18 July 2014 at 11:46 pm #

    Pre-diabetes reminds me of osteopenia – oh goody, here’s someone else to whom we can now prescribe very powerful drugs. We all know these wretched people, now ‘patients’ will be on the drugs for the rest of their lives, as they will inevitably become diabetic or have osteoporosis. As you say, the red flag should immediately entail a complete lifestyle and diet change; this is the only way to undo the damage and to heal the body. My husband is a case in point – 6 years ago he was told he was borderline diabetic, he was prescribed ACE inhibitors, beta blockers and the dreaded statins, all of which made him feel wretched. With a complete overhaul of lifestyle, he last lost, and kept off,15kg, with a BMI of 22 – we walk 50 miles a week with our spaniels and feel marvellous. Needless to say, I managed to get him off all of the medications. Thanks to the recent NICE recomendations, both of us are prime candidates for statins; our doctors are well aware that we will not touch them with a bargepole!

  4. nikki 18 July 2014 at 11:54 pm #

    although I agree that diagnosing people with a label. I think its a good idea to let patients know if they have to be careful of their simple carb and sugar intake. I don’t think they should be put on medication immediately.

    • gregw 20 July 2014 at 12:49 pm #

      I agree. My dad was told he pre diabetes. Ive had type 1 diabetes for 25 years so did glucose testing on him and got him on a low carb diet, moderate fat and upped his protein. His post meal glucose dropped to normal ranges, he said he hadnt felt as good in years. Plus he lost weight but thats plateuing now as expected from a low carb diet.
      It can be easy to treat with diet but fixing diet doesnt create millions more patients to feed drugs supplied by big pharma.

  5. Christopher Palmer 19 July 2014 at 1:20 am #

    Medical diagnosis is now so sophisticated there are very few ‘healthy’ people remaining.

    • M. Cawdery 19 July 2014 at 10:17 am #

      Medical diagnosis these days is “herd diagnosis” based on epidemiological studies. It is not an individual diagnosis. Statin therapy is an example of this. The large majority of the “herd” so diagnosed will not suffer a heart attack or benefit from treatment in the next 10 years.

      Risk is a medical ruse to get the herd on treatment for trivial benefits to the individual but vast profits for the commercial interests!

  6. OldTech 19 July 2014 at 1:59 am #

    I know that I wished that I had been diagnosed with pre-diabetes. When I was diagnosed with an A1c of 6.5 and fasting BG of 139, I was already suffering from diabetic complications. After quickly normalizing my BG most of these symptoms have gone away, but not all. Hopefully with time the remaining symptoms will also dissipate.

    So if I had been told that I was pre-diabetic would that have helped? Would I have gone on a very low carb diet to aggressively control my BG? I don’t know especially given the standard advice. We need to both inform people that they have pre-diabetes and tell them to cut the carbs because they are carb intolerant. I think that I would have responded positively to that combined message.

    And if 50% of the population is pre -diabetic we really need to wake up and deal with our global diet.

  7. helen 19 July 2014 at 6:04 am #

    Carb reduction not only helps pre-diabetics, (if that is what they want to call them), but a low carb diet will reverse full blown type 2 diabetes as well ……………still staggers me that people would rather take a dangerous drug rather than alter their diet sugar addiction is a powerful thing.

  8. Paulc 19 July 2014 at 7:08 am #

    When I was told I was pre-diabetic, I was given the NHS dietary advice, the notorious “eatwell plate”… told to go low fat heart healthy diet… so I followed it to the letter little knowing that all those supposedly healthy low/zero fat items had had sugar added to them… I switched to wholegrain bread… still put on weight, my annual figures continued to get worse (fasting blood glucose level) until I was finally declared to be a full blown T2 diabetic…

    I was basically accused of backsliding on the diet as it had made no difference so therefore I must not have been following it…

    It was only finding Dr. Briffa’s book “Escape The Diet Trap” and also getting myself a blood glucose meter and doing some googling and lurking in the forums that turned things round.

    My fasting blood Glucose levels are now nearly normal… my HBa1c is normal… but I can’t eat carbs… I have a limit of no more than 25 grams in any one meal if I want to keep my blood glucose level within safe limits.

  9. Carol 19 July 2014 at 8:17 am #

    A very low carb diet does not necessarily reverse T2 diabetes, otherwise I would now have normal blood sugar readings! Even with a total of 30g carb per day, BG readings are still slightly elevated.
    A diagnosis of pre-diabetes AND advice to go low carb might well have prevented my current situation.

    • Jackie Bushell 19 July 2014 at 9:26 am #


      Low magnesium levels may be worth looking into if you haven’t already. I recommend Dr Carolyn Dean’s ‘The Magnesium Miracle’ 2007 edition. She explains that low levels are extremely common even on a ‘healthy diet’ and that without sufficient magnesium insulin is not properly secreted, and what does get into the bloodstream doesn’t work correctly. At cell level, magnesium is required to open pathways into the cell for the entrance of blood sugar. If magnesium is in short supply, sugar stays in the bloodstream. She also says that some researchers have concluded that hypertension and insulin resistance may just be different expressions of deficient levels of cellular magnesium.

      Interestingly, supplementing calcium without balancing it with extra magnesium will also likely cause magnesium deficiency, and how many people today are told to supplement calcium by the NHS, with never a thought of their magnesium levels?

    • M. Cawdery 19 July 2014 at 10:11 am #

      Have you ever had your insulin levels measured? This is a measurement that seems to be rarely done in the NHS, which I find odd given the uses of sulphonureas to boost insulin (low insulin) while high insulin is associated with CVD.

      • Janet B 19 July 2014 at 4:19 pm #

        When I asked about this at the surgery, the practice nurse told me they don’t do that because it’s too expensive. Ditto HDL and LDL particle size. It would be good and useful to know though. I thought about ‘going private’ but as I am an OAP I fear it would be beyond my means. (Also, a little voice says ‘why should I?’

  10. Wilson 19 July 2014 at 8:23 am #

    I’m an active woman, slim, good low carb diet, plenty of exercise and have always had a FBG of 5.2-5.6 – I seem to be pre-diabetic!

  11. Janet B 19 July 2014 at 9:44 am #

    HFLC advice shouldn’t be dished out just to “prediabetics” and type two diabetics – it should be EVERYONE.
    No pasta, no sugar, no rice, almost no bread, no potatoes, limited fruit (with the exception of berries) – I never felt better thanks to the likes of Drs. Briffa, Kendrick et al – lean and raring to go.
    Thanks, guys.

    • gregw 20 July 2014 at 12:59 pm #

      Id disagree with what you say, its as much a blanket statement as the nhs recommending a low fat high carb diet. If youre sedentary or pre diabetic then certainly drop the carbs and probably good idea to drop wheat completely for most people, if you’re active and participate in weight training, sports a few times a week its a good idea to eat rice and protein post training to help build and maintain muscle. Id suggest everyone who can does resistance training and the eats carbs at the suitable time.

  12. M. Cawdery 19 July 2014 at 10:07 am #

    Prof Yudkin reported on sucrose and its damaging effects back in the late 1960s-early 1970s and even published a book “Pure, White and Deadly………” But of course one Ancel Keys held the limelight with his hicarb/lofat views and Yudkin was ignored.

    RESULT: Obestity, metabolic syndrome, diabetes and Type 3 diabetes (some researchers believe Alzheimer’s is a diabetic condition)

    I find it frustrating that the youngsters of today are accusing sugar as if it was a brand new research finding; it merely displays their ignorance.

    Senneff et al (European Journal of Internal Medicine Volume 22, Issue 2 , Pages 134-140, April 2011) has also demonstrated an association between hicarb intake and Azheimer’s which ties in with the diabetes Type 3 concept.

    My question is whether the medical establishment, Big Commerce et al and their experts will ever consider this aspect. Somehow I doubt it – scientific integrity has been replaced as a priority by money, power and status!

  13. Jennie B 19 July 2014 at 10:33 am #

    Well I seem to remember back in the early 70′s when I did my nursing training, that FBG of under 8 was considered to be normal. We are all diabetic these days it seems.
    Also patients who actually were diabetic had very strict carb intake. Non of this ‘eat whole grain bread, cereal,potatoes, rice, pasta,low fat, that seems to be recommended today by the ‘experts’ hey ho!!

  14. JamesK 19 July 2014 at 11:25 am #

    I’ve never seen a clear explanation of diet impact on HbA1c.

    Is a HbA1c high level only due to a sustained high-carb diet over the previous 3 months?

    Or, is a high level due to consuming just a few meals being high carb, say 5% of the meals over a 3-month period?

    Another way to pose the question: If one has primarily a low-carb lifestyle, does a moderate number of high-carb (50-75g) meals impact HbA1c significantly (dangerously?)?

  15. Karen 19 July 2014 at 3:54 pm #

    what gets me with the treatment of anyone labeled diabetic is that along with metformin there are also prescribed blood pressure medications and statin medication. These medications destroy the body in a way that increases blood sugar. Also metformin does have side effects one of them include arthritis. I know this because I just met formin and
    develop arthritis.

    I’m also concerned with the ever expanding guidelines for sickness. ..soon it will be so large that no one can escape it.

    We are already seeing what happens when large groups become chemically addicted to medications. ..after the patent is gone all of a sudden there’s a shortage. ..which has the effect of tremendously driving up prices…in some cases over a 1000%.

  16. Wilson 19 July 2014 at 5:58 pm #

    James, low carbing can actually make people more insulin resistant for a bit as the body down regulates enzymes needed to deal with glucose. it’s a well known phenomenon called physiological insulin resistance. So I think a couple of high carb meals while you’re low carbing may cause greater glucose spikes than if someone on a ‘normal diet’ ate them.

  17. JamesK 19 July 2014 at 11:44 pm #

    Reply to Wilson:

    I understand what you suggest about ‘spikes’. But do the handful of spikes (say 5 to 10% of one’s meals) really make a significant impact on HbA1c measurement?

    Per my own readings on the subject, it’s not clear at all. If the overall HbA1c measurement is primarily reflecting a small percentage of spikes, it’s a questionable indicator, IMHO.

    • Wilson 20 July 2014 at 11:10 am #

      If there are only a few glucose spikes then I don’t think it’s likely to make a great deal of difference to overall HbA1C

  18. Peter Jensen 20 July 2014 at 3:59 am #

    Ok. But I think it’s important to identify metabolic syndrome, which is what pre diabetes is a part of, so the proper measure can be taken to try to reverse it and prevent potential complications which include besides diabetes, obesity, heart disease, dyslipidemia ie high triglycerides and low HDL. The proper measure namely consists of low carb high fat Atkins type diet.

  19. Soul 24 July 2014 at 6:51 pm #

    The other day I saw on a TV a TV personality mention what he did when diagnosed with pre-diabetes. He is a younger guy, in his early 30s. When told that he was likely to develop full blown diabetes in the near future he weighed close to 400lbs. When the news came in, he “immediately” signed up for lap-ban surgery. He also changed his diet. As he said, he never fully realized the impact of what he ate could have on his health. It wasn’t mentioned what he now eats, other than saying “real food”. Since the diagnosis, and procedure he has lost close to 200lbs. He was looking great, and wasn’t in the same danger as before with developing diabetes.

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