Validation of Insulin Sensitivity and Secretion Indices Derived from the Liquid Meal Tolerance Test

Abstract

A liquid meal tolerance test (LMTT) has been proposed as a useful alternative to more labor-intensive methods of assessing insulin sensitivity and secretion. This substudy, conducted at the conclusion of a randomized, double-blind crossover trial, compared insulin sensitivity indices from a LMTT (Matsuda insulin sensitivity index [MISI] and LMTT disposition index [LMTT-DI]) with indices derived from minimal model analysis of results from the insulin-modified intravenous glucose tolerance test (IVGTT) (insulin sensitivity index [S(I)] and disposition index [DI]). Participants included men (n = 16) and women (n = 8) without diabetes but with increased abdominal adiposity (waist circumference ≥102 cm and ≥89 cm, respectively) and mean age of 48.9 years. The correlation between S(I) and the MISI was 0.776 (P < 0.0001). The respective associations between S(I) and MISI with waist circumference (r = -0.445 and -0.554, both P < 0.05) and body mass index were similar (r = -0.500 and -0.539, P < 0.05). The correlation between DI and LMTT-DI was 0.604 (P = 0.002). These results indicate that indices of insulin sensitivity and secretion derived from the LMTT correlate well with those from the insulin-modified IVGTT with minimal model analysis, suggesting that they may be useful for application in clinical and population studies of glucose homeostasis.