The Metabolic Syndrome Real or Myth

Assumptions underlying the concept of the Metabolic Syndrome (MS) are implicit rather than explicit. Categorization of patients into have and don't have MS groups is based on five features, any combination of three or more may be used to determine which category they belong to. These features are triglyceride, glucose, and High Density (HD) cholesterol levels, blood pressure and obesity. The number of combinations arising from five features taken three at a time is found by substituting in the following expression: n!/k!(n-k)!; thus 5! /3!(5-3)!=120/12=10 These 10 combinations can be characterized as: ABC, BCD, BDE, CDE, BAD, CAD, CAE, DEA, ABE, BCE where Obesity=A; BP=B; HD Cholesterol=C; Triglycerides=D & Glucose=E. If the metabolic syndrome is a coherent entity the assumption is that any of these combinations of variables will produce very similar categorizations regardless of which of the 10 combinations is used. This is largely true but the above analysis also shows that while the categorizations correctly identify about 58% of the actual cases they also incorrectly identify many others (43%) (See table 1 below). I used data from the well known U.K. Caerphilly study. This does not include glucose levels so I could use up to 4 features only. But it has the advantage of noting an outcome of Myocardial Infarct (MI) followed for over 30 years, which allows verification of the results. The discriminant function technique (SPSS v.26) was used.