Prediabetes

Prediabetes means your blood sugar levels are higher than normal but not high enough for a diagnosis of type 2 diabetes. That is the NHS wording, and it adds that prediabetes puts you at higher risk of diabetes in the future. Diabetes UK, which also calls it borderline diabetes, defines it as an HbA1c of 42 to 47 mmol/mol.

It is diagnosed with a blood test, often a routine one or an NHS Health Check. Diabetes UK says it is more common in people living with overweight or obesity but can also affect people of a healthy weight, and that weight alone does not cause it. Either the body makes too little insulin, or the insulin works less well, which is called insulin resistance.

HbA1c is a blood test that shows your average blood sugar over the last 2 to 3 months. It measures the sugar attached to haemoglobin in your red blood cells, and red blood cells last about that long, which is why it reflects a longer period than a finger-prick test. Diabetes UK describes a finger-prick test as a snapshot of one moment.

HbA1c is the usual test for prediabetes, and it is also used to diagnose and monitor type 2 diabetes. Conditions that affect red blood cells, such as haemolytic anaemia, sickle cell anaemia and thalassaemia, can make it less accurate, and a clinician may use a different test. The NHS Health Check, for people aged 40 to 74 without an existing condition, may include a blood sugar test. Privately, single blood tests at London clinics and labs cost about £43 to £99.

A normal HbA1c is below 42 mmol/mol (6%), prediabetes is 42 to 47 mmol/mol, and 48 mmol/mol (6.5%) or above is the range for type 2 diabetes. Those are the bands Diabetes UK uses:

• below 42 mmol/mol (below 6%): the normal range
• 42 to 47 mmol/mol: prediabetes
• 48 mmol/mol (6.5%) or above: type 2 diabetes

UK results are given in mmol/mol, which has been the standard unit since 2009, and older results used a percentage. Your HbA1c can shift if you are unwell, very stressed or taking some medicines, so a clinician reads it with your history. If you already have diabetes, your diabetes team may set you a personal target.

Prediabetes usually has no symptoms, which is why it tends to be found on a routine blood test or an NHS Health Check. Because there are no symptoms, Diabetes UK says it is important to know the risk factors:

• getting older
• a family history of diabetes
• living with overweight or obesity
• more fat stored in and around the organs, often shown by a high waist-to-height ratio
• a Black African, African Caribbean or South Asian background
• poor quality sleep
• smoking

Diabetes UK’s Know Your Risk tool estimates your risk of type 2 diabetes over the next 10 years from your age, height, weight and waist. If symptoms such as thirst, tiredness or passing more urine do appear, that can mean type 2 diabetes has developed, and you should see your GP.

A prediabetes diet is built on vegetables, fruit, wholegrains and foods close to their natural state, with fewer sugary drinks and refined carbohydrates. Diabetes UK names the foods most linked to a higher risk as:

• sugary drinks
• refined carbohydrates, such as white bread, white rice and sugary breakfast cereals
• red and processed meats, such as bacon, ham and sausages

Diabetes UK suggests small goals you can keep for the long term, such as swapping sugary fizzy drinks for diet versions for a month and building from there. If you are overweight, portion size matters too, because Diabetes UK says weight loss is likely to have the biggest impact on reversing prediabetes. It also asks you to speak to your GP before making big changes to your diet.

Prediabetes can often be reversed, which Diabetes UK defines as your HbA1c returning to a normal level, below 42 mmol/mol. It does not go away on its own, and there is no certainty it will reverse. Any fall still helps, because it keeps your HbA1c from creeping into the type 2 range and helps lower cholesterol and blood pressure.

If you are living with overweight or obesity, Diabetes UK says weight loss is likely to have the biggest impact, and that losing even a small amount of weight can help lower average blood sugar. If losing weight is hard, or you are a healthy weight, changes to diet and activity can still help. Diabetes UK calls a three-month target unlikely to be realistic and advises small changes you can keep. A medical weight loss programme tracks that change through repeat HbA1c results.

If you already have type 2 diabetes, weight loss should be planned with your diabetes team, because they manage any treatment you take and need to know what is changing. A private programme should share its results with your GP, so your care stays in one place.

Some people with type 2 diabetes go into remission. Diabetes UK describes remission as blood sugar staying in a healthy range over the long term through lifestyle changes alone, and its researchers used an HbA1c of 48 mmol/mol or below to define it. Diabetes UK also stresses that type 2 diabetes is still a serious condition, so the yearly HbA1c test it says you are entitled to still matters. Remission is what people usually mean by reversing type 2 diabetes, and a clinician can tell you whether it is a realistic aim for you.

The Healthier You NHS Diabetes Prevention Programme is a nine-month lifestyle programme for people at risk of type 2 diabetes, and Diabetes UK says people with prediabetes should be offered a place or prevention advice, depending on where they live. NHS England says it gives personalised support to manage your weight, eat more healthily and be more physically active, and that you can choose a face-to-face group or a digital version with apps and health coaches.

Referral comes through your GP practice if you are at risk. You can check your risk first with Diabetes UK’s Know Your Risk tool, or with a free NHS Health Check if you are 40 to 74. If you have had gestational diabetes, the NHS says you can refer yourself. NHS England reports that the programme has reduced new diagnoses of type 2 diabetes in England.

See your GP if you think you could have prediabetes or are at higher risk, and see them promptly if you notice symptoms that can mean type 2 diabetes has developed. Diabetes UK lists:

• going to the toilet more often, especially at night
• feeling more tired than usual
• losing weight without trying
• genital itching or thrush
• cuts and wounds taking longer to heal
• blurred vision
• feeling extremely thirsty

If you are underweight, Diabetes UK says losing more weight will not help prediabetes and is unsafe to try, so see your GP instead. If eating or your weight is causing you distress, speak to your GP or contact Beat.

A first assessment arranged by Medical Weight Loss London at UNTIL Soho starts from your HbA1c. It measures your waist, weight and blood pressure, and arranges HbA1c with a lipid profile, liver function, thyroid function and a full blood count, because the NHS groups raised blood sugar with blood pressure and blood fats in metabolic syndrome. If you have a recent HbA1c from your GP, bring it. First assessments at London clinics cost about £150 to £310, with tests on top (what a programme costs).

The terms are explained in the weight management glossary. Ask what to get checked and UNTIL Health Concierge arranges the appointment with a registered clinician.