What is the A1C (Hemoglobin A1C) level range considered pre-diabetic?

Prediabetes A1C Range

The A1C range for prediabetes is 5.7-6.4%, with individuals in this range having a significantly increased risk of developing diabetes and requiring preventive interventions. 1

Definition and Diagnostic Criteria

• Prediabetes is defined as an A1C level between 5.7% and 6.4%, representing an intermediate metabolic state between normal glucose metabolism and diabetes 1
• This range corresponds to other prediabetic states including impaired fasting glucose (IFG) of 100-125 mg/dL and impaired glucose tolerance (IGT) of 140-199 mg/dL on a 2-hour oral glucose tolerance test 1
• The American Diabetes Association (ADA) formally established this range in their diagnostic criteria, recognizing it as a significant risk factor for both diabetes development and cardiovascular disease 1

Risk Stratification Within Prediabetic Range

• The risk of developing diabetes increases progressively throughout the prediabetic A1C range, with a disproportionate increase at higher levels 1
• Individuals with A1C between 5.7-6.0% have a moderate 5-year diabetes risk of 9-25% 2
• Those with A1C between 6.0-6.4% have a substantially higher 5-year diabetes risk of 25-50% and a relative risk 20 times higher compared to those with A1C of 5.0% 1, 2
• Due to this gradient of risk, more intensive interventions and vigilant follow-up are recommended for those with A1C levels above 6.0% 1

Clinical Implications and Interventions

• All individuals with A1C in the 5.7-6.4% range should be informed about their increased risk for both diabetes and cardiovascular disease 1
• Preventive strategies focusing on weight loss and increased physical activity are recommended for all individuals with prediabetes 1
• Evidence from the Diabetes Prevention Program shows that lifestyle interventions are effective for people with A1C levels both below and above 5.9% 1
• Monitoring should be more frequent for those at the higher end of the prediabetic range (A1C > 6.0%) due to their substantially increased risk 1

Important Considerations and Limitations

• The risk of diabetes with any glycemic measure is a continuum, extending below the lower limit of the prediabetic range 1
• While A1C of 5.7-6.4% is the established range, some studies suggest that individuals with A1C as low as 5.5% may have increased diabetes risk compared to those with lower levels 1
• The World Health Organization and some other diabetes organizations use different cutoffs for impaired fasting glucose (110 mg/dL rather than 100 mg/dL), which may affect how prediabetes is defined in different countries 1
• A1C may be less sensitive for detecting at-risk individuals than fasting glucose or glucose tolerance tests, particularly among non-Hispanic whites 3
• Baseline A1C is a stronger predictor of subsequent diabetes development than fasting glucose in many populations 1

Risk Factors That Warrant Screening

• Individuals with BMI ≥25 kg/m² (or ≥23 kg/m² in Asian Americans) with additional risk factors should be screened for prediabetes 1
• Those with A1C in the prediabetic range should be monitored regularly, with more frequent follow-up for those with A1C >6.0% 1
• The risk of progression from prediabetes to diabetes varies by population and is influenced by factors such as ethnicity, with higher detection rates among African Americans and Hispanics compared to non-Hispanic whites 3