Perché il glucosio conta

Prediabetes: the window where a sensor earns its keep

Aggiornato 2026-08-07

Questa guida non è ancora tradotta nella tua lingua, quindi è mostrata in inglese.

Risposta breve

What should I do about prediabetes?

Prediabetes means glucose above normal but below the diabetes threshold. Between 5% and 10% of people with it progress to diabetes each year — and a similar proportion return to normal glucose levels. Lifestyle change is the intervention with the strongest evidence, cutting progression by more than half in a large randomised trial.

Come leggere le etichette dell’evidenza

Ogni affermazione di questa pagina porta un’etichetta che indica quanto peso può reggere. Descrive la solidità del risultato, non il prestigio della rivista.

  • Evidenza solidaUn grande studio randomizzato, una coorte seguita a lungo, o la concordanza di più studi.
  • Evidenza preliminareReale, ma sottile — piccolo, breve, osservazionale o non ancora replicato.
  • ControversoRicercatori competenti sono apertamente in disaccordo. Non scegliamo noi da che parte stare.

What the diagnosis actually means

Prediabetes is a threshold, not a disease process: glucose measures higher than normal and lower than the diabetes cut-off. The physiology underneath — insulin resistance together with early beta-cell dysfunction — was under way before the numbers crossed the line.

The word frightens people more than the statistics justify, and it should also not be dismissed. Both halves of the following are true, and popular coverage usually reports only one of them.

Che cosa dicono le prove

  • Between 5% and 10% of people with prediabetes progress to diabetes each year, and a similar proportion revert to normoglycaemia.1

    Evidenza solida

  • Prediabetes is associated with early nephropathy, chronic kidney disease, small fibre neuropathy, retinopathy and raised macrovascular risk — the harms begin before the diabetes threshold is reached.1

    Evidenza solida

What actually changes the outcome

The Diabetes Prevention Program randomised 3,234 people at high risk to a lifestyle programme, metformin, or placebo. The lifestyle arm aimed at 7% weight loss and 150 minutes of activity a week. Over an average of just under three years it reduced new diabetes by 58%, beating metformin's 31%.

Put in terms of individual benefit: seven people going through the lifestyle programme for three years prevented one case of diabetes. That is an unusually strong result for a behavioural intervention.

Che cosa dicono le prove

  • A structured lifestyle programme reduced progression to type 2 diabetes by 58% and metformin by 31%, compared with placebo, over an average 2.8 years of follow-up.2

    Evidenza solida

  • Around seven people had to complete the lifestyle programme for three years to prevent one case of diabetes; for metformin the figure was about fourteen.2

    Evidenza solida

Where a sensor fits — and where it does not

Notice what was in the trial and what was not. The proven intervention is weight loss and activity. No continuous glucose monitor was involved, and no trial has since shown that adding one improves the result.

The defensible case for wearing a sensor at this stage is narrower and still worth something: it makes an abstract instruction concrete. "Eat fewer refined carbohydrates" becomes a curve you watched change after you walked for ten minutes. That is a plausible aid to doing the thing that works. It is not itself the thing that works, and anyone selling it as such is ahead of the evidence.

A fortnight of wear costs a fraction of a year of it, and for this purpose a fortnight may be all you need. Our cheapest-to-try ranking exists for exactly this reader.

Che cosa dicono le prove

  • The interventions shown to prevent progression from prediabetes are behavioural and pharmacological; continuous glucose monitoring has not been shown to add benefit to them.1,2

    Evidenza solida

Domande frequenti

Can prediabetes be reversed?
Yes, and it happens often. Roughly as many people with prediabetes return to normal glucose levels each year as progress to diabetes. Lifestyle change substantially shifts those odds in your favour.
Do I need a CGM if I have prediabetes?
No. The interventions with proven benefit are weight loss and physical activity, neither of which requires a sensor. A sensor may help you carry them out by making the effect of a meal or a walk visible, but it has not been shown to improve outcomes on its own.
How long should I wear one for?
If the goal is learning how your own meals and activity affect you, a single sensor's wear — usually ten to fifteen days — covers most of what you will learn. Continuous wear costs many times more and has no evidence behind it at this stage.

Bibliografia

  1. 1.Tabák AG, Herder C, Rathmann W, Brunner EJ, Kivimäki M (2012). Prediabetes: a high-risk state for diabetes development. The Lancet. 10.1016/S0140-6736(12)60283-9
  2. 2.Knowler WC, Barrett-Connor E, Fowler SE, Hamman RF, Lachin JM, Walker EA, Nathan DM (Diabetes Prevention Program Research Group) (2002). Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin. New England Journal of Medicine. 10.1056/NEJMoa012512

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