[The metabolic syndrome -- a controversial diagnostic concept]

The metabolic syndrome is a heterogeneous complex that is clinically interpreted as an indicator of an increased risk of diabetes mellitus, cardiovascular morbidity and mortality. The diagnosis of metabolic syndrome is made, if at least three out of five factors - dysglycemia, visceral obesity, increased triglycerides, decreased HDL cholesterol, arterial hypertension - are present. Both the popularity and criticism of the metabolic syndrome have increased over recent years. One crucial problem are the currently existing definitions. This is illustrated on the basis of recent primary-care data from Germany, showing a prevalence ranging from 19% to 31% depending on the definition used. The debate about the rationale of the concept in terms of risk prediction for cardiovascular diseases points at one weakness of the concept. The entire discussion is mainly influenced by different approaches: a simple pedagogic approach, a pathophysiological approach, with insulin resistance as main focus of research, and a clinical-epidemiologic approach, where a cluster of different risk factors for cardiovascular disease risk prediction forms the initial scientific interests. Acknowledging these different perspectives might help reduce the confusion associated with the meaning and usefulness of the metabolic syndrome.