Prediabetes: what to do next

Reviewed by the JForH team · 2026-10-30

Prediabetes in the UK is an HbA1c of 42–47 mmol/mol (6.0–6.4%). Below 42 is normal and 48 or above is type 2 diabetes. In England you can join Healthier You, the free NHS Diabetes Prevention Programme, through your GP or, in some areas, by registering yourself. People referred to it were 20% less likely to develop type 2 diabetes. NICE advises an HbA1c check at least once a year.

What does an HbA1c of 42–47 mmol/mol mean?

It means prediabetes. Your blood glucose has been higher than normal over the past two to three months, but not high enough for type 2 diabetes.

HbA1c	Result
Below 42 mmol/mol (below 6.0%)	Normal
42–47 mmol/mol (6.0–6.4%)	Prediabetes
48 mmol/mol (6.5%) or above	Type 2 diabetes

The NHS also uses a fasting blood glucose of 5.5–6.9 mmol/L to refer people for prevention support. Your GP record may call it non-diabetic hyperglycaemia. Diabetes UK calls it borderline diabetes too. They all mean the same.

How common is prediabetes?

Common. Diabetes UK estimates it affects around 1 in 12 people. Many don't know they have it, because it rarely causes symptoms. It's usually found on a blood test done for another reason, or at an NHS Health Check.

Is HbA1c 42 bad?

It's the bottom of the prediabetes range, so it's a warning, not a diagnosis. Diabetes UK says healthy changes can prevent type 2 diabetes or bring blood glucose back to normal. Your GP should refer you to a type 2 prevention course or give you advice.

What is the NHS Diabetes Prevention Programme (Healthier You)?

It's a free NHS programme in England to help people with prediabetes lower their risk of type 2 diabetes. In North East London, for example, it runs for nine months and you can choose:

face-to-face group sessions
a digital programme on your phone or computer
remote sessions

It covers eating, activity and weight. The provider and details vary by area.

Who can join Healthier You?

adults aged 18 or over
an HbA1c of 42–47.9 mmol/mol, or a fasting glucose of 5.5–6.9 mmol/L, from a blood test in the last 12 months
registered with a GP in England

If you've had diabetes in pregnancy, you may qualify even with lower results. You can't join if you're pregnant or your results already show type 2 diabetes.

How do I get referred to the Diabetes Prevention Programme?

Ask your GP, practice nurse or pharmacist. Any health professional with a recent HbA1c result can refer you.

In some areas you can register yourself online. You'll need your NHS number, your blood test result and its date, and your height and weight. Self-referral has closed in some areas, so if the website turns you away, ask your surgery.

Does the programme work?

An observational study published in PLOS Medicine in 2023 compared 18,470 people referred to the programme with 51,331 who weren't. Those referred were 20% less likely to develop type 2 diabetes.

Put another way, over three years the researchers expected 127 in every 1,000 referred people to develop type 2 diabetes, against 154 in every 1,000 who weren't referred. That's from being referred, not from finishing the course, so people who complete it may do better.

I'm South Asian. Is my risk higher?

Yes. Diabetes UK says South Asian, Black African and African Caribbean people are at higher risk of type 2 diabetes from age 25, compared with 40 for white Europeans, and at a lower BMI of 23. If that's you, ask for an HbA1c test earlier, even if you feel well.

The Healthier You food guide includes South Asian, African and Caribbean meals, with portion ideas for chapatis, rice and dal.

What can I do myself while I wait?

Lose some weight if you're carrying extra. It doesn't have to be a lot to make a difference.
Cut back on sugary drinks, sweets and large portions of white bread, rice, pasta and potatoes.
Choose porridge or eggs over sugary cereals at breakfast.
Walk more. A brisk walk after your evening meal is an easy start.
Stop smoking, and keep alcohol within the low-risk guideline.

How often should my HbA1c be checked?

At least once a year, NICE says, for people with an HbA1c of 42–47 mmol/mol. Use the same type of test each time so results compare. If you get symptoms such as thirst, peeing more or tiredness, ask for a test sooner.

What happens if my HbA1c reaches 48?

48 mmol/mol (6.5%) or over is in the type 2 diabetes range. If you have no symptoms, your GP will usually repeat the test to confirm it before making a diagnosis. If it isn't confirmed, you stay on yearly checks.

A diagnosis isn't the end of the road. If you're diagnosed within the last 6 years and meet the other criteria, you may be able to join the NHS Type 2 Diabetes Path to Remission Programme through your GP.

Can I get tested if nobody has offered it?

Yes. The NHS Health Check is a free check for adults aged 40 to 74 without an existing condition, offered every 5 years. It can include a blood sugar test.

If you live in Scotland, Wales or Northern Ireland, ask your GP what prevention support is available locally. Healthier You is an NHS England programme.

Find out where your numbers stand (free check)

Common questions

What is a prediabetes HbA1c in the UK?

42–47 mmol/mol (6.0–6.4%). Below 42 is normal and 48 mmol/mol or above is type 2 diabetes.

Is HbA1c 42 prediabetes?

Yes, 42 mmol/mol is the start of the prediabetes range. It's a warning, and a good time to make changes.

How do I get on the NHS Diabetes Prevention Programme?

Ask your GP, nurse or pharmacist to refer you. In some areas you can self-register online with your NHS number, recent blood test result and date, height and weight.

Who is eligible for Healthier You?

Adults 18 and over in England with an HbA1c of 42–47.9 mmol/mol or a fasting glucose of 5.5–6.9 mmol/L in the last 12 months. People with a history of diabetes in pregnancy may qualify with lower results.

Does the Diabetes Prevention Programme work?

A 2023 study found people referred were 20% less likely to develop type 2 diabetes: 127 in 1,000 over three years, against 154 in 1,000 not referred.

How often should prediabetes be checked?

NICE advises an HbA1c test at least once a year.

Can prediabetes go back to normal?

Often, yes. Diabetes UK says healthy changes can bring blood glucose back to normal or prevent type 2 diabetes, though results vary.

At what age should South Asian people be tested?

Diabetes UK says South Asian, Black African and African Caribbean people are at higher risk from age 25, and at a BMI of 23.

Sources

Last updated: 2026-10-30. Educational information, not medical advice. Talk to your doctor before changing your treatment.