Just Diagnosed With Prediabetes? What the Evidence Says Works

Your blood test came back, and your clinician said "prediabetes". You may feel relieved it is not diabetes, or worried that diabetes is coming. The good news is that prediabetes is a warning sign you can act on. This guide explains the numbers and what the strongest studies show.

What prediabetes means

Prediabetes means your blood sugar (glucose) is higher than normal but not high enough to be called diabetes. It usually has no symptoms.

People with prediabetes have a higher chance of developing type 2 diabetes. They also have a higher risk of heart disease. But prediabetes is not a sure path to diabetes. Many people stay stable, and many return to normal.

What your doctor looks at

Clinicians use three tests. The cutoffs for prediabetes differ between Canada and the US.

A1C

A1C (glycated hemoglobin) shows your average blood sugar over about 3 months.

• Diabetes Canada: 6.0% to 6.4% is prediabetes [2].
• American Diabetes Association (ADA): 5.7% to 6.4% is prediabetes [3].
• Both: 6.5% or higher is in the diabetes range [2] [3].

Fasting plasma glucose

This is measured after at least 8 hours without food.

• Diabetes Canada: 6.1 to 6.9 mmol/L is impaired fasting glucose [2].
• ADA: 100 to 125 mg/dL (about 5.6 to 6.9 mmol/L) is impaired fasting glucose [3].
• Both: 7.0 mmol/L (126 mg/dL) or higher is in the diabetes range.

Two-hour oral glucose tolerance test

You drink a sugar drink and your glucose is measured 2 hours later.

• 7.8 to 11.0 mmol/L (140 to 199 mg/dL) is impaired glucose tolerance in both countries [2] [3].
• 11.1 mmol/L (200 mg/dL) or higher is in the diabetes range.

A diabetes diagnosis usually needs a repeat test to confirm, unless you have clear symptoms and a very high glucose.

Who gets screened

• In the US, the US Preventive Services Task Force (USPSTF) recommends screening adults aged 35 to 70 who have overweight or obesity [4].
• In Canada, the Canadian Task Force on Preventive Health Care recommends first assessing risk with a validated risk tool, such as FINDRISC or CANRISK, then testing people at high risk with A1C every 3 to 5 years, and people at very high risk every year [5].

What the evidence says works

The Diabetes Prevention Program

The Diabetes Prevention Program (DPP) is the landmark trial. It enrolled more than 3,200 US adults with overweight and impaired glucose levels [1]. People were assigned to one of three groups:

• An intensive lifestyle program
• Metformin, a diabetes pill
• Placebo

Over about 3 years [1]:

• Lifestyle reduced the chance of diabetes by 58% compared with placebo.
• Metformin reduced it by 31%.
• Each year, about 11 in 100 people on placebo developed diabetes, compared with about 8 in 100 on metformin and about 5 in 100 in the lifestyle group.

What the lifestyle program asked for

The goals were modest and specific [1]:

• Lose about 7% of body weight. For a person who weighs 90 kg, that is about 6 kg.
• Do at least 150 minutes a week of moderate activity, such as brisk walking.
• Eat a healthy, lower-calorie, lower-fat diet.

Participants met with coaches often, especially at the start. Support made a difference.

Where to find a program

In the US, the CDC-led National Diabetes Prevention Program offers lifestyle change programs based on the DPP, in person and online [6]. In Canada, programs vary by province. Ask your clinician, a dietitian, or your local diabetes education centre.

Metformin

Metformin also lowered risk in the DPP, though less than lifestyle [1]. The benefit was larger in younger people and those with higher body weight. It is not approved specifically for prediabetes in Canada or the US, but clinicians sometimes offer it to higher-risk people. Talk to your clinician or pharmacist about whether it fits you.

Other steps that help

• Treat high blood pressure and cholesterol, because heart risk is already higher.
• Stop smoking.
• Sleep well. Poor sleep and sleep apnea can worsen blood sugar.
• Limit sugary drinks and highly processed foods.
• Find activity you enjoy so you keep doing it.

Prediabetes and your heart

Prediabetes often comes with other risk factors, such as high blood pressure, high triglycerides, low HDL cholesterol, and extra belly fat. Together, these raise the risk of heart attack and stroke. That is why your clinician may also check your blood pressure and cholesterol and estimate your 10-year heart risk.

The same lifestyle changes that lower blood sugar also help these other risk factors. Small steps add up:

• A 10-minute walk after meals
• Water instead of sugary drinks
• More vegetables, beans, and whole grains
• Regular sleep times

Questions to ask your clinician

• Which test showed prediabetes, and what was my result?
• How likely am I to develop diabetes in the next few years?
• Is there a diabetes prevention program near me or online?
• How much weight loss would make a difference for me?
• Should I consider metformin?
• What is my blood pressure and cholesterol, and do they need treatment?
• When should I be tested again?

When to get care quickly

Prediabetes itself is not an emergency. Get medical care soon if you have strong thirst, frequent urination, blurred vision, or weight loss without trying. These can be signs of diabetes. Go to the emergency department for vomiting, deep fast breathing, confusion, or severe drowsiness.

Bottom line

Prediabetes is common and often reversible. Canadian and US cutoffs differ a little, so check which ones your lab used. The best evidence shows that modest weight loss and regular activity cut the chance of diabetes by more than half.

Primary AI can show you the guideline and study sources behind this topic in plain language, so you can bring better questions to your appointment.