Definitions of the Insulin Resistance Syndrome

The Adult Treatment Panel III: metabolic syndrome

Richard Pasternak (Boston, MA) discussed the deliberations that led the National Cholesterol Education Program Adult Treatment Panel (ATP) III to propose a new definition of the metabolic syndrome (1) and the impact of this proposal in heightening awareness of the insulin resistance syndrome (IRS). Coronary heart disease (CHD) is the main cause of death in the developed world, and Pasternak noted that contrary to general perceptions, malignancy is only approximately half as frequent a cause of mortality as CHD among women. The concept of metabolic syndrome extends in a precise way an important subset of patients at high risk for CHD. The definition was created to be clinically practical, evidence based, and applicable to existing datasets. The ATP did not find adequate evidence to recommend routine measurement of insulin sensitivity or of inflammatory markers. The 2-h glucose was not included because it was similarly felt not to add sufficient numbers of persons to justify the additional effort involved. The panel has been criticized for not calling the metabolic syndrome a CHD equivalent, but Pasternak pointed out that at that time there was no evidence that this was the case. Rather, the presence of the metabolic syndrome was felt to accentuate the risk accompanying elevated LDL cholesterol, mediated through existing and emerging risk factors. Clinical trials show evidence for modification of atherogenic dyslipidemia, blood pressure, and the prothrombotic state (with aspirin, which the panel recommended only for persons with CHD but which Pasternak suggested is appropriate for all persons with the syndrome) in persons undergoing LDL-lowering therapy. The primary management strategy should be to reverse its root causes of obesity and physical inactivity, with an …