Insulin Resistance and Hypertension

Insulin resistance refers to the reduction in insulinmediated glucose uptake in insulin-sensitive tissues, specifically in skeletal muscle. As a compensatory response, hyperinsulinemia ensues to maintain normal blood glucose levels. In epidemiological studies, fasting insulin level is commonly used as a surrogate marker of insulin resistance. In normoglycemic subjects, fasting insulin correlated well with whole-body glucose uptake (r 0.68) as measured by the “gold standard” euglycemic hyperinsulinemic clamp method, although the correlation was lower in individuals with impaired glucose tolerance or type 2 diabetes mellitus.1 Although fasting insulin is a reasonable measure of insulin resistance, it is potentially confounded by variability in insulin secretion. Thus, the indexes derived from fasting insulin and glucose, such as the Homeostasis Model Assessment (HOMA),2 the Quantitative Insulin Sensitivity Check Index (QUICKI),3 and the insulin sensitivity index (ISI) developed by Gutt and coworkers,4 have been more widely used to assess insulin resistance in clinical and populationbased studies.