HOMA-IR (Homeostasis Model Assessment for Insulin Resistance)
A widely used surrogate marker for insulin resistance calculated from fasting glucose and fasting insulin levels.
Warnings:
- HOMA-IR is validated for epidemiological studies and research settings, not for individual diagnosis
- Cutoff values vary by population; some use >2.0, >2.5, or >3.0 as abnormal
- Formula requires fasting glucose in mmol/L; if using mg/dL, convert first (mg/dL / 18 = mmol/L)
- Not validated for patients with established diabetes, severe insulinopenia, or on insulin therapy
- QUICKI and fasting glucose/insulin ratio are alternative insulin resistance surrogates
Note: HOMA-IR was described by Matthews et al. (1985). Reference: Bonora et al. validated cutoff of 3.0 for highest quartile. In clinical practice, HOMA-IR >2.0-2.5 is often considered elevated. HOMA-beta can be calculated as: 20 x Fasting Insulin / (Fasting Glucose - 3.5).
Fasting glucose in mmol/L. To convert from mg/dL: divide by 18
Fasting insulin in microU/mL (or mU/L, same units)
References
- Assessment of preferred methods to measure insulin resistance - Medical Science Monitor / PMC (2021)
- The Homeostasis Model Assessment-insulin Resistance Index Is Inversely Associated with Serum Carotenoids - PMC (2020)