Insulin sensitivity is the ability of insulin to stimulate glucose uptake, promote peripheral glucose disposal, and suppress hepatic glucose production. The primary site of glucose dispose is skeletal muscle. The gold standard method for the determination of insulin sensitivity is the hyperinsulinemic-euglycemic insulin clamp. However, the clamp technique is expensive and complex. Surrogate methods to determine insulin sensitivity include fasting insulin and glucose, oral glucose tolerance test, and intravenous glucose tolerance test. The most common calculations using fasting insulin and glucose are fasting glucose to insulin ratio, homeostasis model assessment of insulin resistance (HOMA), and quantitative insulin sensitivity check index (QUICKI). The HOMA and QUICKI models are mathematical estimates of beta cell function and insulin resistance.
Impaired insulin sensitivity or insulin resistance precedes glucose intolerance in the...