Is the Metabolic Syndrome Passè?

Much clinical research effort has been spent in the last three decades on the metabolic syndrome.  A syndrome is a “group of symptoms that collectively indicate or characterize a disease, psychological disorder, or other abnormal condition”.  It was generally agreed that the metabolic syndrome requires 3 of the following risk factors to be present: (a) waist size over 40 inches in men, or 35 inches in women.  (b) serum triglyceride level over 150 mg/dL.  (c) serum HDL ('good') cholesterol below 40 mg/dL in men, or 50 mg/dL in women. (d) blood pressure over 130/85 mm Hg (either number), or taking blood pressure medication.  (e) fasting blood sugar over 110 mg/dL.  People with the syndrome were shown to be at increased risk of cardiovascular disease, stroke, type 2 diabetes, and gout.

Since its general acceptance many clinicians have tried adding or changing one or more of the criteria.  An alternative name, the insulin resistance syndrome, tries to tie the name to a likely cause.  Some cardiovascular specialists have suggested the syndrome is an unnecessary construct, and that physicians can deal better with the individual risk factors, or a combination of them, without dignifying them by calling them a syndrome. 

Now a report in the journal Circulation online describes an analysis of the varying prognoses in groups of patients with different combinations of the risk factors belonging to the metabolic syndrome.  Data from 3,078 participants from the Framingham Offspring Study were used; they attended examinations in 1987, 1991, and 1995. Information on cardiovascular disease and mortality up to 2007 was correlated with the risk factors.

The number subjects with the metabolic syndrome almost doubled in 10 years’ follow-up, with the greatest increases in numbers with elevated fasting blood sugar levels and waist sizes.  The most frequent factor when metabolic syndrome was diagnosed was high blood pressure (present in 77% of cases), while the existence of increased waist size was most predictive of later metabolic syndrome.  Those participants who developed the syndrome with a combination of increased waist size, high blood pressure, and high fasting sugar had a 2.36-fold increase in cardiovascular events and a 3-fold increase in mortality. 

The authors of this study cry for attention to be paid to the triad of symptoms (waist size, blood pressure, and blood sugar) that they’ve shown to be most responsible for serious outcomes.  It seems clear that these three factors are more relevant, and that one can give much less attention to a diagnosis of metabolic syndrome that’s founded mainly on the two basic lipid factors.  In other words, instead of the metabolic syndrome, we should concentrate on uncovering and treating the triad of  obesity-hypertension-diabetes.