Linkage of epidemiologic evidence with the clinical aspects of metabolic syndrome

Metabolic syndrome (MetS) is characterized by a cluster of cardiovascular risk factors, such as hypertension, glucose intolerance, high triglycerides, and a low high density lipoprotein-cholesterol level. MetS is known to be associated with cardiovascular diseases. In order to diagnose MetS, definitions such as National Cholesterol Education Program Adult Treatment Panel III, American Heart Association/National Heart Lung and Blood Institute, International Diabetes Federation, World Health Organization, European Group for the Study of Insulin Resistance and American College of Endocrinology are widely used. However, using different criteria may lead to confusion regarding the diagnosis and treatment of patients with MetS in the primary care setting. Our objected was to review 3 aspects concerning MetS using the Metabolic Syndrome Research Initiatives study of 123892 healthy Koreans (1994-2001) that had a maximum follow-up of 12 years. The 3 aspects were reviewed by determination of the association of MetS with the development of atherosclerotic cardiovascular disease (ASCVD) and ischemic heart disease (IHD). Based on our findings, each metabolic factor associated with MetS was not weighted equally. The hazard ratio (HR) was higher in individuals with higher glucose compared with the HR in individuals with higher body mass index. Individuals with pre-MetS (having 1 or 2 metabolic factors) had 1.5-2.3 fold higher risk of developing ASCVD and IHD in both genders. In the presence of MetS, both singly and in combination, precede the development of ASCVD and IHD and individuals with pre-MetS must not be ignored as there is no apparent threshold in defining MetS. Furthermore, MetS may complement the Framingham Risk Score and can be used as the first line approach to treat the ASCVD or IHD.