Prediabetes Is Not a Disease. It Is a Warning With Unusually Good Evidence Behind It
The label is contested, the thresholds differ between guidelines, and most people who have it never progress. It is also the one point in this whole condition where a trial showed you can change the outcome by more than half.
Friday, July 10, 2026/4 min read
Few medical labels annoy doctors as reliably as this one. Prediabetes is not a disease. You cannot feel it, it damages nothing on the day you are told about it, and a large share of people who receive the label will never develop diabetes at all.
It is also the only stage of this condition where a properly conducted trial demonstrated that you can cut the outcome by more than half. Both things are true, and holding them together is the entire skill of reading a prediabetes result correctly.
What number makes someone prediabetic?
Three different tests, three different ranges, and they do not always agree with each other.
- HbA1c between 5.7 and 6.4 per cent under American Diabetes Association criteria. At 6.5 and above, it is diabetes.
- Fasting plasma glucose between 100 and 125 mg/dL, or 5.6 to 6.9 mmol/L, in ADA terms. At 126 mg/dL or 7.0 mmol/L, it is diabetes.
- Two-hour glucose on an oral tolerance test between 140 and 199 mg/dL, or 7.8 to 11.0 mmol/L. At 200 or 11.1, it is diabetes.
Note the disagreement built into that list. The World Health Organization has historically used a higher fasting threshold to define impaired fasting glucose than the ADA does, which means a person can be prediabetic in one guideline and normal in another without their body changing at all. That is not a scandal, it is what happens when you draw a line across a continuous variable, but it should temper how much weight anyone puts on a single borderline reading.
Does prediabetes always become diabetes?
No, and anybody who tells you otherwise is misreading the statistics.
A meaningful proportion of people with prediabetes revert to normal glucose regulation on their own. Others stay exactly where they are for a decade or more. Progression is a probability, not a schedule, and the risk rises with how high in the range you sit, your weight trajectory, family history, and whether you had gestational diabetes.
What the label genuinely tells you is that your glucose regulation is already working harder than it should to keep you in range. The pancreas is compensating. Prediabetes is the sound of that compensation, and the reason it is worth acting on is that intervening while the pancreas still has reserve is very different from intervening after it has run out.
What actually reduces the risk?
This is where prediabetes stops being a nagging label and becomes genuinely useful, because we have unusually strong data.
The Diabetes Prevention Program randomised people with impaired glucose tolerance to an intensive lifestyle programme, to metformin, or to placebo. The lifestyle arm reduced the incidence of type 2 diabetes by 58 per cent. Metformin reduced it by 31 per cent.
Two details in that result deserve more attention than the headline.
First, lifestyle beat the drug, and it was not close. That is an unusual finding in modern medicine and it has held up in long-term follow-up.
Second, the lifestyle arm was not a pamphlet. It was a structured programme targeting modest, sustained weight loss of around 7 per cent and about 150 minutes of activity a week, with real support behind it. When people say lifestyle change did not work for them, they usually mean advice did not work for them, which is a different thing and a failure of the health system rather than the patient.
Why does this matter so much in this region?
Because the pool of people who do not know is enormous.
The IDF Diabetes Atlas puts around 43 per cent of adults with diabetes worldwide as undiagnosed, overwhelmingly type 2. Behind every one of those there is a larger group sitting in the prediabetic range who have never had the test at all.
In the Gulf, where adult prevalence runs above 20 per cent in several countries, that undiagnosed pool is not a rounding error. It is the single largest opportunity in regional public health, and it is reachable with a blood test that costs almost nothing.
What should you do with a prediabetes result?
Not panic, and not ignore it. Three things.
- Confirm it. A single borderline HbA1c is a reason for a second test, not a diagnosis. Values near a threshold move, and HbA1c has specific conditions under which it reads falsely high or low.
- Aim at the number the trial used. Around 7 per cent of body weight and roughly 150 minutes of movement a week. Not perfection, not a transformation, a target that was actually tested.
- Get the rest of the picture checked. Prediabetes rarely arrives alone. Blood pressure, lipids and liver are worth looking at in the same visit, because insulin resistance affects all of them and the combination carries more risk than any single number.
The label is imperfect. The window it describes is real, and it is the widest one you will get.
Published in The Outspoken Digest
Editorial desk
Outspoken Digest Health DeskMedicine, public health and the research behind the headlines, read carefully.
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