From the Guidelines
Prediabetes is defined by a hemoglobin A1c (HbA1c) level between 5.7% and 6.4%. This range indicates that blood glucose levels are higher than normal but not yet high enough to be diagnosed as type 2 diabetes, which is defined as an HbA1c of 6.5% or higher. For comparison, normal HbA1c levels are below 5.7%.
Key Points
- Prediabetes is a critical warning sign that you're at increased risk of developing type 2 diabetes, heart disease, and stroke.
- The good news is that prediabetes can often be reversed through lifestyle modifications including weight loss of 5-7% of body weight if overweight, regular physical activity (at least 150 minutes per week of moderate-intensity exercise), and dietary changes focusing on reduced calorie intake and healthier food choices.
- Regular monitoring of HbA1c levels every 1-2 years is recommended for those with prediabetes to track progress and detect any progression toward diabetes early, as supported by the most recent guidelines and recommendations for laboratory analysis in the diagnosis and management of diabetes mellitus 1.
Evidence Summary
The definition of prediabetes as an HbA1c level between 5.7% and 6.4% is based on the most recent and highest quality study available, which provides guidelines and recommendations for laboratory analysis in the diagnosis and management of diabetes mellitus 1. This range is consistent with other studies, including those published in 2010 1 and 2014 1, which also support the use of HbA1c levels to diagnose and manage diabetes. However, the most recent study 1 provides the most up-to-date and authoritative guidance on this topic.
From the Research
HbA1c Level Indicative of Prediabetes
- The HbA1c level indicative of prediabetes is between 5.7% to 6.4% 2, 3, 4
- This range is defined by the American Diabetes Association (ADA) as an intermediate stage between normal glucose regulation and diabetes 2, 3, 4
- HbA1c levels between 5.7% to 6.4% are associated with an increased risk of developing type 2 diabetes and cardiovascular events 2, 5, 4
Diagnosis and Management of Prediabetes
- Prediabetes can be diagnosed using a fasting glucose level, a glucose level measured 2 hours after a 75-g oral glucose load, or a glycated hemoglobin level (HbA1c) 2
- Lifestyle modification, including calorie restriction, increased physical activity, self-monitoring, and motivational support, is a first-line therapy for prediabetes 2, 3
- Metformin is also effective in reducing the risk of diabetes among individuals with prediabetes, particularly for women with prior gestational diabetes and individuals younger than 60 years with a body mass index of 35 or greater 2, 4