Evaluation Of Insulin Sensitivity From A Minimal Model Adapted To Oral Glucose Tests
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F. Di Nardo, F. Casagrande, F. Carle, M. Boemi, P. Fumelli, P. Morosini & R. Burattini
Recently, we proposed a new methodology for clinical evaluation of insulin sensitivity, SI, and the rate constant of glucose absorption, kabs, from oral glucose tests. This methodology relies on a minimal model of glucose kinetics coupled with a structural description of gastric emptying of glucose and its conversion into the rate of systemic absorption from the gut. The aim of the present study was to test the reproducibility of SI and kabs provided by our model using two data sets from a 300 min frequently sampled oral glucose tolerance test: a full 22-sample data set (OGTT300/22) and a reduced 11-sample data subset (OGTT300/11). Nine subjects, not affected by the metabolic syndrome, participated in the study. Mean (95% confidence interval) values of 22 I S and 22 abs k obtained from the OGTT300/22 were 12.3 (8.8-15.8) ×10-4 min-1/(µU/ml) and 1.80 (1.31-2.29) ×10-2 min-1, respectively. Mean values of 11 I S and 11 abs k obtained from the OGTT300/11 were 11.3 (7.6-15.0) ×10-4 min-1/(µU/ml) and 1.75 (1.19- 2.31) ×10-2 min-1, respectively. The concordance of the full and reduced paired samples in providing SI and kabs estimates is supported by intraclass correlation coefficients of 0.93 and 0.97, respectively. Parameter estimates and model based simulations of the rate of glucose appearance into plasma, Ra(t), were comparable with data in the literature. In conclusion, our model appears a potentially useful tool to estimate insulin sensitivity and the rate constant of systemic glucose absorption from reduced oral glucose tests. Keywords: glucose kinetics, gastric emptying, gut model, OGTT.
glucose kinetics, gastric emptying, gut model, OGTT.