Decreased insulin sensitivity (or insulin resistance) is a major risk factor for type 2 diabetes mellitus and renal and cardiovascular disease. It is the key component and, possibly, a pathogenetic factor of the metabolic syndrome - a clustering of arterial hypertension, obesity, impaired glucose tolerance, dyslipidemia, coagulation abnormalities, albuminuria and increased cardiovascular risk - that may precede or accompany type 2 diabetes.