Validation of the insulin sensitivity index (ISI0,120): comparison with other measures

The purpose of this study was to explore possible calculations using oral g lucose tolerance test (OGTT) values in order to develop a simple measure of insulin sensitivity. We devised a formula for an insulin sensitivity index , ISI0,120, that uses the fasting (0 min) and 120 min post-oral glucose (OG TT) insulin and glucose concentrations. It appears to be generalizable acro ss a spectrum of glucose tolerance and obesity. Most importantly, our data show that ISI0,120 correlates well, when applied prospectively in comparati ve studies, with the insulin sensitivity index obtained from the euglycemic hyperinsulinemic clamp (r = 0.63, P < 0.001). This correlation was demonst rably superior to other indices of insulin sensitivity such as the HOMA for mula presented by Matthews, and performed comparably to the computerized HO MA index. Measurement of insulin sensitivity has traditionally been possibl e only in research settings because of the invasiveness and expense of the methods used. Clinical investigators have therefore sought more practical m ethods to obtain an index of insulin sensitivity. Such an index should appr oximate insulin sensitivity as measured by the euglycemic hyperinsulinemic clamp (M). We present ISI0,120, a simple yet sensitive measure of insulin s ensitivity which is adaptable for use in clinical settings as well as large epidemiologic studies. (C) 2000 Elsevier Science Ireland Ltd. All rights r eserved.