What does an Hemoglobin A1c (HbA1c) level of 5.6 indicate in terms of diabetes risk?

What Does an A1C of 5.6% Mean?

An A1C of 5.6% falls just below the prediabetes threshold and indicates you are at increased risk for developing diabetes, though not yet in the formal prediabetes category. 1, 2

Risk Category Classification

• Your A1C of 5.6% is technically in the "normal" range since it falls below the American Diabetes Association's prediabetes cutoff of 5.7%. 1, 2
• However, this does NOT mean your diabetes risk is negligible—the relationship between A1C and diabetes risk exists on a continuum, with risk increasing even within the "normal" range. 3
• Linear regression data from NHANES shows that an A1C of 5.6% corresponds to a fasting plasma glucose of approximately 110 mg/dL, which is in the impaired fasting glucose range. 3

Your Actual Diabetes Risk

Individuals with A1C between 5.5-6.0% have a 5-year diabetes incidence of 9-25%, which is three to eight times higher than the general U.S. population. 3, 4

• This represents a moderately increased relative risk for developing diabetes over the next 5 years. 4
• Your risk is substantially higher than someone with an A1C below 5.0%, but lower than someone with A1C 5.7-6.4% (the formal prediabetes range). 4
• The risk curve is curvilinear, meaning as your A1C rises even slightly from this point, your diabetes risk will increase disproportionately. 3

Clinical Implications and What You Should Do

You should be counseled about diabetes prevention strategies now, even though you're technically below the prediabetes threshold. 3

Key Actions:

• Implement lifestyle modifications immediately: Focus on weight loss (if overweight) and increased physical activity. 3, 2
• Assess additional risk factors that compound your diabetes risk: obesity (especially abdominal), family history of diabetes, hypertension, and dyslipidemia. 3
• Consider more intensive preventive interventions if you have multiple risk factors, as the American Diabetes Association suggests the optimal A1C threshold for initiating prevention falls somewhere in the 5.5-6.0% range. 3

Important Caveat:

Evidence from the Diabetes Prevention Program demonstrates that lifestyle interventions are effective for people with A1C levels both below and above 5.9%, meaning you can benefit from preventive measures at your current level. 3

Monitoring Recommendations

• Regular follow-up is warranted given your elevated risk, though not as intensive as for those with A1C ≥5.7%. 3
• Repeat A1C testing should be performed to monitor trajectory, as progression toward 5.7% or higher would move you into the formal prediabetes category requiring more aggressive intervention. 2
• Your healthcare provider should conduct a global cardiovascular risk assessment, as the metabolic abnormalities associated with elevated A1C also increase cardiovascular disease risk. 3

Common Pitfall to Avoid

Do not dismiss this A1C value as "normal" simply because it's below 5.7%—this is a critical window for prevention. 3 Many patients and clinicians fail to act on A1C values in the 5.5-5.6% range, missing an opportunity to prevent progression to diabetes when interventions are most effective. 3