Is prediabetes (impaired glucose regulation) harmful?

From the Guidelines

Yes, there is substantial evidence that prediabetes is harmful to health, increasing the risk of cardiovascular disease, kidney disease, and nerve damage, and ultimately leading to a higher risk of mortality. Prediabetes is characterized by blood glucose levels that are higher than normal but not yet high enough to be diagnosed as type 2 diabetes (typically fasting glucose of 100-125 mg/dL or HbA1c of 5.7-6.4%) [ 1 ]. Even at these intermediate levels, prediabetes is associated with increased risk of cardiovascular disease, kidney disease, and nerve damage. About 5-10% of people with prediabetes progress to type 2 diabetes annually, and up to 70% will eventually develop diabetes in their lifetime without intervention [ 1 ].

Key Risks and Considerations

• Prediabetes also increases risk of stroke, cognitive decline, and early mortality [ 1 ].
• The risk of progression to diabetes and associated comorbidities can be individualized based on factors such as age, BMI, and other comorbidities [ 1 ].
• Characteristics of individuals at particularly high risk of progression to diabetes include BMI ≥35 kg/m², those at higher glucose levels, and individuals with a history of gestational diabetes [ 1 ].

Prevention and Management

• Lifestyle modifications, including weight loss of 5-7% of body weight, 150 minutes of moderate physical activity weekly, and dietary changes focusing on reduced calories, lower carbohydrates, and increased fiber, can prevent or delay progression to diabetes [ 1 ].
• Medications like metformin may be considered for high-risk individuals, though lifestyle changes remain the cornerstone of treatment [ 1 ].
• Regular monitoring with annual blood tests is recommended for those with prediabetes to track progression or improvement [ 1 ].

From the Research

Definition and Prevalence of Prediabetes

• Prediabetes is an intermediate stage between normal glucose regulation and diabetes, affecting 1 in 3 adults in the US and approximately 720 million individuals worldwide 2.
• It is defined by a fasting glucose level of 100 to 125 mg/dL, a glucose level of 140 to 199 mg/dL measured 2 hours after a 75-g oral glucose load, or glycated hemoglobin level (HbA1C) of 5.7% to 6.4% or 6.0% to 6.4% 2.
• The prevalence of prediabetes is increasing worldwide, with experts projecting that more than 470 million people will have prediabetes by 2030 3.

Risks Associated with Prediabetes

• Prediabetes is associated with increased risk of diabetes, cardiovascular events, and mortality 2, 3.
• Approximately 10% of people with prediabetes progress to having diabetes each year 2.
• A meta-analysis found that prediabetes at baseline was associated with increased mortality and increased cardiovascular event rates 2.
• Prediabetes is also associated with early forms of nephropathy, chronic kidney disease, small fibre neuropathy, diabetic retinopathy, and increased risk of macrovascular disease 3.

Management and Prevention of Prediabetes

• Intensive lifestyle modification, consisting of calorie restriction, increased physical activity, self-monitoring, and motivational support, decreased the incidence of diabetes by 6.2 cases per 100 person-years during a 3-year period 2.
• Metformin decreased the risk of diabetes among individuals with prediabetes by 3.2 cases per 100 person-years during 3 years 2.
• Lifestyle modification is associated with a larger benefit than metformin 2.
• Randomized clinical trials have demonstrated that lifestyle and pharmacologic interventions can be cost-effective, prevent diabetes, and improve cardiovascular risk factors in adults with prediabetes 4.