Table 2

AUC, specificity, sensitivity, PPV, and NPV at the optimal cutoff value

Index/testingAUC (95% CI)Optimal cutoffSensitivitySpecificityPPVNPV
IVGTT
    Fasting glucose0.49 (0.40–0.59)960.230.880.460.74
    Fasting insulin0.59 (0.50–0.68)10.230.820.290.320.8
    FPIR0.57 (0.48–0.66)1560.760.40.340.81
    HOMA-IR0.58 (0.49–0.67)2.640.660.480.330.77
    FPIR-to-HOMA-IR ratio*0.66 (0.57–0.74)49.220.680.610.410.83
OGTT
    Fasting glucose0.49 (0.40–0.59)880.470.560.270.7
    2-h glucose0.67 (0.59–0.76)1140.620.710.460.83
    Peak C-peptide0.56 (0.47–0.66)5.30.70.460.340.79
    AUC C-peptide0.56 (0.47–0.65)5950.810.310.330.8
  • *AUCs are significantly better than AUC fasting glucose derived from an IVGTT or OGTT (P < 0.01).