Defining the metabolic syndrome: Resolving unresolved issues?

Abstract

Background Several definitions exist for the metabolic syndrome. In concert with the blood pressure and glucose criteria of the NCEP definition, it has now been suggested that the use of fibrates and nicotinic acid be incorporated into the dyslipidemia criteria. While statins are the drugs most widely prescribed for lowering LDL-cholesterol, they also affect triglyceride and HDL-cholesterol levels. The aims of the present study were (1) to investigate how adding lipid-lowering therapy to the NCEP definition might influence the prevalence of the metabolic syndrome and (2) to compare the characteristics of patients identified according to the newly proposed IDF definition with those identified according to the NCEP definition. Methods We conducted a cross-sectional study on 2373 patients with clinically manifest vascular disease. In order to allow for the influence of lipid-lowering therapy on the identification of patients with the metabolic syndrome, the NCEP definition was modified in two ways. In NCEP-rev1, the use of lipid-lowering agents fulfilled the hypertriglyceridemia criterion; in NCEP-rev2, triglycerides and HDL-cholesterol plasma concentrations were recalculated for lipid-lowering agents. Results The prevalence of the metabolic syndrome was 41% according to the NCEP definition, 50% according to the NCEP-rev1, 44% according to the NCEP-rev2, and 52% according to the IDF definition. Patients identified only with the NCEP definition had lower HDL-cholesterol, higher triglycerides, and higher fasting glucoses levels than patients only diagnosed with the IDF definition. Conclusion Adding the use of lipid-lowering drugs to the NCEP definition may lead to the identification of an additional group of patients at an elevated risk for cardiovascular diseases and diabetes. The NCEP definition of the metabolic syndrome identifies patients with a worse cardiovascular risk profile than patients qualifying for the metabolic syndrome with the IDF definition in a cohort of patients with clinical manifestations of vascular disease.