Validation of simple indices to assess insulin sensitivity based on the oral glucose tolerance test in the Japanese population

The homeostasis model assessment (HOMA) represents a simple index for evaluating insulin sensitivity, but clinical use is limited. Insulin sensitivity indices calculated from plasma glucose and plasma insulin concentrations after an oral glucose tolerant test (OGTT) have been proposed, but have not been validated in the Japanese population. We compared these indices with the euglycemic hyperinsulinemic clamp technique to evaluate the predicting insulin sensitivities in 77 Japanese subjects with varying degrees of glucose tolerance (normal glucose tolerance, n=40; impaired glucose tolerance, n=22; and type 2 diabetes mellitus, n=15). Insulin sensitivity was measured by the euglycemic hyperinsulinemic glucose clamp technique using an artificial pancreas, and expressed as the M-value. Weak inverse correlations existed between the HOMA index and M-values ( r=−0.227, P=0.0468). An alternative index calculated by Matsuda's formula correlated with the M-value ( r=0.450, P=0.0001). A second index calculated by Stumvoll's formula also correlated with the M-value ( r=0.641, P=0.0001). Finally, a third index calculated by Gutt's formula also significantly correlated with the M-value ( r=0.526, P=0.0001). All three indices are applicable for clinical use. The second index is the most sensitive measure of insulin sensitivity in the Japanese population.