TABLE 3

Insulin sensitivity and B-cell function according to various models of calculation

Parameter [reference]Healthy control subjectsFirst-degree relatives of type 2 diabetic patientsType 2 diabetic patientsSignificance (P value, ANOVA)Reference
B-cell function
 HOMA B-cell function index (% of normal)67 ± 749 ± 563 ± 150.2742
 Insulin/glucose [basal] ([mU/l]/[mg/dl])0.06 ± 0.010.05 ± 0.00.09 ± 0.010.1955
 Insulin/glucose [hyperglycemia] ([mU/l]/[mg/dl])0.09 ± 0.010.07 ± 0.010.10 ± 0.020.34no reference
Insulin sensitivity
 HOMA insulin resistance index (fold normal)1.31 ± 0.95*1.03 ± 0.12*3.56 ± 1.010.000242
 Glucose infusion/insulin ([mg · kg−1 · min−1]/ [mU/l])§0.43 ± 0.090.46 ± 0.050.25 ± 0.130.19no reference
 Fasting Belfiore index ([l/mU] · [dl/mg])0.078 ± 0.0080.107 ± 0.012*0.045 ± 0.0140.000656
 FIRI ([l/mU] · [dl/mg])1.11 ± 0.2*0.88 ± 0.1*3.55 ± 0.980.000357
  • Data are means ± SE. P values were calculated by ANOVA with Duncan’s post hoc test to describe differences among the three groups of patients.

  • *

    * Significant difference (P < 0.05) versus type 2 diabetic patients;

  • significant difference (P < 0.05) versus healthy control subjects;

  • hyperglycemia refers to the time point 30 min (see Fig. 1), i.e., before start of the GIP infusion;

  • §

    § glucose infusion was calculated for the period 15–30 min (see Fig. 1) and related to the mean insulin concentrations at 15 and 30 min.