## Abstract

Recently, a new approach has been proposed to estimate insulin sensitivity (S _{I} from an oral glucose tolerance test or a meal using an "integral equation". Here, we improve on the "integral equation" by resorting to a "differential equation" approach. The classic glucose kinetics minimal model was used with the addition of a parametric model for the rate of appearance into plasma of oral glucose (Ra). Three behavioral models of Ra were proposed: piecewise-linear (P), spline (S) and dynamic (D). All three models performed satisfactorily allowing a precise estimation of S _{I} and a plausible reconstruction of Ra. Mean S _{I} estimates were virtually identical: S _{I} ^{P} = 6.81 ± 0.87 (SE); S _{I} ^{S} = 6.53 ± 0.80; and S _{I} ^{D} = 6.62 ± 0.79. S _{I} strongly correlated with the integral-equation index (I) S _{I} ^{I}: r = 0.99, p <0.01 for models D and S, and r = 0.97, p <0.01 for P. Also, S _{I} compared well with insulin sensitivity estimated from intravenous glucose tolerance test in the same subjects (r = 0.75, p <0.01; r = 0.71, p <0.01; r = 0.73, p <0.01, respectively, for P, S, and D models versus S ^{IVGTT}. Finally, the novel approach allows estimation of S _{I} from a shorter test (120 min): model P yielded S _{I} ^{R} = 7.16 ± 1.0 (R for reduced) which correlated very well with S _{I} ^{P} and S _{I} ^{I} (respectively, r = 0.94, p <0.01; r = 0.95, p <0.01) and still satisfactorily with S _{I} ^{IVGTT} (r = 0.77, p <0.01).

Original language | English |
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Pages (from-to) | 419-429 |

Number of pages | 11 |

Journal | IEEE Transactions on Biomedical Engineering |

Volume | 49 |

Issue number | 5 |

DOIs | |

Publication status | Published - 2002 |

## Keywords

- Glucose kinetics
- IVGTT
- Parameter estimation
- Physiological model
- Rate of appearance

## ASJC Scopus subject areas

- Biomedical Engineering