### Abstract

OBJECTIVE - The goal of this study was to evaluate the performance of surrogate measures of insulin sensitivity and insulin secretion. RESEARCH DESIGN AND METHODS - The homeostasis model assessment (HOMA) of insulin resistance (IR) and the insulin sensitivity index (S_{i}) from oral glucose tolerance test (OGTT) were compared with the M value from a hyperinsulinemic- euglycemic clamp in 467 subjects with various degrees of glucose tolerance. Endogenous glucose production (EGP) and hepatic insulin sensitivity were determined in a subset (n = 143). Insulin secretion was estimated as the HOMA β-cell index and as the insulinogenic index from the first 30 min of the OGTT (I/G30) and compared with the first-phase insulin response (FPIR) to an intravenous glucose tolerance test (n = 218). RESULTS - The M value correlated with the HOMA-IR (r = -0.591, P < 0.0001) and the S_{i} (r = 0.533, P < 0.0001) indexes in the total study group. HOMA-IR correlated with basal EGP in the total study group (r = 0.378, P < 0.0005) and in subjects with diabetes (r = 0.330, P = 0.01). However, neither HOMA-IR nor S_{i} correlated significantly with the M value in subjects with impaired fasting glucose (IFG) (r = -0.108, P = 0.5; r = 0.01, P = 0.9) or IFG/impaired glucose tolerance (IGT) (r = -0.167, P = 0.4; r = 0.09, P = 0.6). The HOMA-IR correlated with hepatic insulin sensitivity in the whole study group (r = -0.395, P < 0.005) as well as in the IFG/IGT subgroup (r = -0.634, P = 0.002) and in the diabetic subgroup (r = -0.348, P = 0.008). In subjects with IFG/IGT, hepatic insulin sensitivity was the most important determinant of HOMA-IR, explaining 40% of its variation. The HOMA β-cell index showed a weak correlation with FPIR in the whole study group (r = 0.294, P = 0.001) but not in the subgroups. In contrast, the I/G30 correlated with FPIR in the whole study group (r = 0.472, P < 0.0005) and in the IFG/IGT subgroup (r = 0.493, P < 0.005). CONCLUSIONS - HOMA-IR is dependent upon both peripheral and hepatic insulin sensitivity, the contribution of which differs between subjects with normal and elevated fasting glucose concentrations. These discrepancies develop as a consequence of a nonparallel deterioration of the variables included in the equations with worsening of glucose tolerance.

Original language | English (US) |
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Pages (from-to) | 2204-2210 |

Number of pages | 7 |

Journal | Diabetes care |

Volume | 27 |

Issue number | 9 |

DOIs | |

State | Published - Sep 1 2004 |

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### ASJC Scopus subject areas

- Internal Medicine
- Endocrinology, Diabetes and Metabolism
- Advanced and Specialized Nursing

### Cite this

*Diabetes care*,

*27*(9), 2204-2210. https://doi.org/10.2337/diacare.27.9.2204