The Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) is a widely utilized physiological calculation that provides a robust estimation of a patient's insulin resistance.
The Pathology of Insulin Resistance
In the early stages of metabolic syndrome, the body's cells become resistant to the effects of insulin. To maintain a normal blood sugar level, the pancreas (specifically the beta cells) compensates by pumping out massive amounts of insulin. Therefore, a patient may have a perfectly normal fasting glucose (e.g., 85 mg/dL) but severe underlying metabolic dysfunction because it requires a fasting insulin level of 25 µU/mL to keep it there. HOMA-IR reveals this hidden dysfunction.
HOMA-IR = (Fasting Insulin × Fasting Glucose) / Constant. Constant is 405 for mg/dL and 22.5 for mmol/L.
Interpreting the Results
The lower the HOMA-IR value, the higher the insulin sensitivity (which is good).
- A healthy, highly insulin-sensitive individual will typically have a HOMA-IR of < 1.0.
- A score > 1.9 indicates early insulin resistance.
- A score > 2.9 indicates significant insulin resistance, heavily correlating with the development of Type 2 Diabetes, cardiovascular disease, and non-alcoholic fatty liver disease (NAFLD).