Does a patient with a hemoglobin A1c (HbA1c) of 5.9 and sugar cravings have insulin resistance?

Does This Patient Have Insulin Resistance?

Yes, a patient with HbA1c of 5.9% and sugar cravings likely has insulin resistance, as this HbA1c level falls within the prediabetes range (5.7-6.4%) which is strongly associated with both insulin resistance and impaired β-cell function. 1, 2

Understanding the HbA1c of 5.9%

An HbA1c of 5.9% definitively places this patient in the prediabetes category (defined as 5.7-6.4%), indicating substantially increased risk for developing type 2 diabetes. 1, 2

• Patients with HbA1c between 5.5-6.0% have a 5-year diabetes incidence of 9-25%, which is 3-8 times higher than the general population. 1, 2
• Those with HbA1c of 5.7-6.4% have a 25-50% risk of developing diabetes within 5 years and a relative risk 20 times higher compared to HbA1c of 5.0%. 1

Evidence of Insulin Resistance at This HbA1c Level

Direct metabolic studies confirm that insulin resistance is present at HbA1c ≥5.7%:

• Research using gold-standard hyperinsulinemic euglycemic clamp studies demonstrates that individuals with HbA1c of 5.7-6.4% exhibit significantly lower insulin sensitivity compared to those with HbA1c <5.7%, even after adjusting for age, gender, and BMI. 3
• These same individuals show reduced β-cell function (measured by disposition index), indicating both core pathophysiological defects of type 2 diabetes are already present. 3
• HbA1c correlates significantly with insulin resistance indices across the glycemic spectrum, with stronger correlations in those with normal glucose tolerance. 4

Clinical Significance of Sugar Cravings

While sugar cravings are not a diagnostic criterion, they may reflect:

• Dysregulated glucose-insulin dynamics characteristic of insulin resistance
• Compensatory hyperinsulinemia that can paradoxically drive hunger and carbohydrate cravings
• Early metabolic dysfunction even before frank diabetes develops

What This Patient Needs

Immediate lifestyle intervention is essential:

• Counseling on weight loss and physical activity to reduce diabetes progression risk is the primary recommendation. 2
• Intensive follow-up with annual HbA1c testing to track progression is necessary. 2
• Assessment of other cardiovascular risk factors (hypertension, dyslipidemia, obesity, family history) should be performed, as insulin resistance increases cardiovascular disease risk. 1, 2

Important Clinical Caveats

HbA1c alone has limitations for detecting insulin resistance:

• HbA1c is less sensitive than fasting glucose or oral glucose tolerance testing for identifying at-risk individuals, particularly in non-Hispanic whites (detecting only 9.9% versus 31.4% in African Americans). 5
• Fasting glucose and 2-hour post-load glucose are more precise correlates of insulin resistance and β-cell function than HbA1c. 5
• However, HbA1c remains a stronger predictor of future diabetes and cardiovascular events than fasting glucose alone in community-based studies. 1

Consider additional testing if clinical suspicion is high:

• Fasting insulin, fasting glucose, and calculation of HOMA-IR can provide more direct assessment of insulin resistance
• Look for physical signs of insulin resistance: acanthosis nigricans, central obesity, hypertension, dyslipidemia, polycystic ovary syndrome 1