HOMA-IR — Homeostatic Model Assessment of Insulin Resistance
HOMA-IR is a validated method for quantifying insulin resistance and beta-cell function from fasting glucose and insulin concentrations. It is widely used in clinical research and practice.
About
HOMA-IR (Homeostatic Model Assessment of Insulin Resistance) was first described by Matthews et al. in 1985 as a mathematical model of the glucose-insulin feedback system in the fasting state. The model is based on the principle that fasting plasma glucose and insulin concentrations are determined by the interaction between insulin secretion from pancreatic beta-cells and insulin sensitivity in peripheral tissues. In insulin-resistant states, higher insulin levels are required to maintain normal glucose homeostasis. The HOMA-IR index is calculated as: (fasting glucose (mg/dL) × fasting insulin (μU/mL)) / 405. The cutoff values for defining insulin resistance vary by population, but commonly used thresholds are: <2.0 (normal), 2.0-2.9 (early insulin resistance), 3.0-5.0 (moderate insulin resistance), and >5.0 (severe insulin resistance). HOMA-IR has been extensively validated against the hyperinsulinemic-euglycemic clamp technique, with correlation coefficients ranging from 0.7 to 0.8 in most studies. It is the most widely used surrogate index of insulin resistance in clinical research, cited in thousands of publications across diverse fields including diabetes, cardiovascular disease, polycystic ovary syndrome, non-alcoholic fatty liver disease, and metabolic syndrome.
Formula
HOMA-IR = (Fasting Glucose (mg/dL) × Fasting Insulin (μU/mL)) / 405
HOMA-IR is calculated by multiplying fasting glucose (in mg/dL) by fasting insulin (in μU/mL) and dividing by 405. The constant 405 accounts for the units of measurement and represents the normal fasting state (approximately glucose 90 mg/dL × insulin 4.5 μU/mL = 405). If glucose is measured in mmol/L, use the constant 22.5 instead. The resulting value is a dimensionless number typically ranging from <1.0 in very insulin-sensitive individuals to >10 in severely insulin-resistant individuals. Higher values indicate greater insulin resistance and increased risk for metabolic disorders.
Score Interpretation
HOMA-IR is the most widely used surrogate measure of insulin resistance in clinical research and practice. It has been instrumental in elucidating the pathophysiology of metabolic syndrome, type 2 diabetes, NAFLD, PCOS, and cardiovascular disease. In epidemiological studies, HOMA-IR independently predicts incident type 2 diabetes, cardiovascular events, and all-cause mortality. Its simplicity makes it practical for large-scale screening, but its precision for individual-level diagnosis is limited compared to clamp techniques.
Normal — 0–1.99
HOMA-IR <2.0. Normal insulin sensitivity.
Management: Continue healthy lifestyle. Routine monitoring.
Early Insulin Resistance — 2–2.9
HOMA-IR 2.0-2.9. Early insulin resistance. Increased metabolic risk.
Management: Lifestyle modification: diet, exercise, weight management. Screen for prediabetes.
Moderate Insulin Resistance — 3–5
HOMA-IR 3.0-5.0. Moderate insulin resistance. Strongly associated with prediabetes and diabetes.
Management: Comprehensive metabolic evaluation. Consider metformin. Endocrinology referral.
Severe Insulin Resistance — 5.01+
HOMA-IR >5.0. Severe insulin resistance. High risk for metabolic complications.
Management: Urgent endocrinology referral. Aggressive intervention. Comprehensive diabetes and CVD risk assessment.
Reference Ranges
| Population | Normal Range | Notes |
|---|---|---|
| Healthy adults with normal glucose tolerance | <2.0 | Cutoffs vary by ethnicity; some populations use lower thresholds |
Dr. Khaled Hassan
Dr. Khaled is a cardiology consultant with experience in acute cardiac care.
View medical review board & editorial policy →Example Calculation
A 55-year-old man with hypertension and BMI 34 kg/m²: fasting glucose 106 mg/dL, fasting insulin 22 μU/mL. HOMA-IR = (106 × 22) / 405 = 2332 / 405 = 5.76. Interpretation: HOMA-IR >5.0 indicates severe insulin resistance. His HbA1c is 6.4%, confirming prediabetes. He is started on metformin 500 mg twice daily and referred for structured lifestyle intervention.
Related Conditions
Related Medications
Common Mistakes
Using non-fasting samples for HOMA-IR calculation
HOMA-IR requires ≥8 hour fasting samples. Postprandial glucose and insulin values do not reflect the homeostatic steady state and will produce invalid results.
Applying the same cutoff to all populations
HOMA-IR cutoffs vary by ethnicity, age, and sex. Some populations (e.g., East Asians) have lower insulin secretion capacity and different optimal cutoffs. Use population-specific references when available.
Frequently Asked Questions
What is a normal HOMA-IR value?
Can HOMA-IR be used in patients on insulin therapy?
References
- Matthews DR, Hosker JP, Rudenski AS, et al. Homeostasis model assessment: insulin resistance and beta-cell function from fasting plasma glucose and insulin concentrations in man. Diabetologia. 1985;28(7):412-419. PubMed
- Wallace TM, Levy JC, Matthews DR. Use and abuse of HOMA modeling. Diabetes Care. 2004;27(6):1487-1495. PubMed
- Bonora E, Targher G, Alberiche M, et al. Homeostasis model assessment closely mirrors the glucose clamp technique in the assessment of insulin sensitivity. Diabetes Care. 2000;23(1):57-63. PubMed