The Role of Prediabetes in the Metabolic Syndrome: Guilt by Association.

The metabolic syndrome (MetS) is a cluster of risk factors for cardiovascular disease (CVD). Prediabetes is defined by either impaired glucose tolerance or by one of the more sensitive or more stringent criterion for impaired fasting glucose (IFG) or HbA1c levels that have been promulgated over the years. IFG is one of the risk factors for CVD included in the definition of the MetS. However, there is very little evidence that IFG is independently associated with CVD regardless of which criterion is used for its diagnosis. The CVD risk of the MetS is related to the other risk factors of central obesity, hypertension, elevated triglyceride, and low high-density lipoprotein cholesterol levels. If the components of the MetS are supposed to be risk factors for CVD, the dysglycemia of prediabetes should not be included in its definition.