EXPLORATION OF SIMPLE INSULIN SENSITIVITY MEASURES DERIVED FROM FREQUENTLY SAMPLED INTRAVENOUS GLUCOSE-TOLERANCE (FSIGT) TESTS - THE INSULIN-RESISTANCE ATHEROSCLEROSIS STUDY

Both abnormal insulin levels and low insulin sensitivity have been imp licated as risk factors for Type II diabetes mellitus and cardiovascul ar disease. While insulin level is relatively simple to assess, direct measurement of insulin sensitivity is much more invasive, costly, and time-consuming, The authors considered eight previously described mea sures or indices of insulin sensitivity derived from the frequently sa mpled intravenous glucose tolerance test (FSIGT). Each one was evaluat ed by strength and consistency of association with insulin sensitivity computed from glucose clamp (S-l(clamp), across three glucose toleran ce groups, including participants with normal glucose tolerance (n = 1 1), impaired glucose tolerance (n = 20), and non-insulin-dependent dia betes mellitus (n = 24). Minimal model analysis (MINMOD S-l(22), based on the 22-sample FSIGT, performed best based on statistical criteria of strong and consistent association with S-l(clamp) . An insulin sens itivity measure similar to that of Galvin et al. (Diabetic Medicine 19 90;9:921-8), defined as glucose disappearance (10-50 minutes) divided by insulin area under the curve above baseline from 0-50 minutes, perf ormed best based on statistical criteria and time-savings. Galvin insu lin sensitivity is simple to calculate, requires only a 50-minute FSIG T, and is significantly (p < 0.001) and not inconsistently (p = 0.12 f or inconsistent association) associated with S-l(clamp) over a wide ra nge of glucose tolerance.