Statistical & Clinical Analysis
Matsuda Index (ISI_comp) Formula: Whole-Body OGTT Hepatic + Peripheral Insulin Sensitivity
Capture both fasting hepatic and post-load skeletal-muscle insulin sensitivity from a 75 g Oral Glucose Tolerance Test using Masafumi Matsuda & Ralph DeFronzo’s composite index 10,000 / SQRT((G_0 * I_0) * (G_mean * I_mean)).
Why fasting HOMA-IR reflects primarily hepatic resistance while Matsuda’s OGTT index captures muscle disposal!
Fasting homeostasis indices such as HOMA-IR = (G_0 * I_0) / 405 reflect predominantly basal hepatic glucose production rather than insulin-stimulated peripheral skeletal-muscle uptake! Masafumi Matsuda and Ralph A. DeFronzo (1999, Diabetes Care — validated directly against gold-standard euglycemic hyperinsulinemic clamps, r = 0.73) combined fasting glucose G_0 (mg/dL) and insulin I_0 (uIU/mL) with mean OGTT glucose G_mean and mean OGTT insulin I_mean across 0–120 minutes: ISI_Matsuda = 10,000 / SQRT((G_0 * I_0) * (G_mean * I_mean))!
Values <= 2.5 (or < 3.0 in metabolic-syndrome cohorts) indicate whole-body insulin resistance, whereas insulin-sensitive individuals typically score 5.0–12.0! For G_0 = 95 mg/dL, I_0 = 14 uIU/mL (HOMA-IR = 3.28), G_mean = 138 mg/dL, and I_mean = 62 uIU/mL, Matsuda ISI = 2.96—rising to 8.10 in an athletic insulin-sensitive profile (G_0 = 84, I_0 = 6, G_mean = 108, I_mean = 28)!
| 75 g OGTT Metabolic Profile (mg/dL & uIU/mL) | Fasting HOMA-IR (G0*I0/405) | Matsuda Whole-Body ISI | Clamp-Correlated Interpretation |
|---|---|---|---|
| G0=95, I0=14; Mean G=138, Mean I=62 | 3.28 | 2.96 | Borderline / Insulin-Resistant Phenotype |
| G0=84, I0=6; Mean G=108, Mean I=28 | 1.24 | 8.10 | High Whole-Body Insulin Sensitivity |
| Zero or Negative Assay Input | Invalid Assay | "Invalid OGTT Glucose or Insulin" | Positive Assay Guard |
Matsuda-DeFronzo Whole-Body Insulin Sensitivity Index = 10,000 / SQRT((G_0*I_0)*(G_mean*I_mean))
Computes ISI_Matsuda from fasting plasma glucose G_0 (B2, mg/dL), fasting insulin I_0 (B3, uIU/mL), mean OGTT glucose G_mean (B4, mg/dL), and mean OGTT insulin I_mean (B5, uIU/mL).
=IF(MIN(B2:B5) <= 0, "Invalid OGTT Glucose or Insulin", ROUND(10000 / SQRT((B2 * B3) * (B4 * B5)), 2))Companion Fasting Hepatic HOMA-IR = (G_0 * I_0) / 405
Evaluates Matthews HOMA-IR in conventional mg/dL and uIU/mL units from the basal time-0 draw.
=IF(MIN(B2:B5) <= 0, "Invalid OGTT Glucose or Insulin", ROUND((B2 * B3) / 405, 2))Try the example
Use the original values or change them to test your understanding.