The Concept of the Metabolic Syndrome Is Just About Dead

I was an early adapter of the concept “metabolic syndrome”.  After all, it made a lot of sense to lump the factors together – overweight, high fasting blood sugar, high blood pressure, abnormal blood lipids (high triglycerides, low high-density cholesterol) – as they were frequently found together in the same person.  It wasn’t long before the metabolic syndrome was widely accepted as a distinct entity, although there were a few skeptics.  Patients labeled as having the syndrome were found to be at increased risk of having a heart attack (myocardial infarction, or MI), and a range of treatments were prescribed to address the abnormalities presented by the syndrome.  Recently, however, the question has been raised:  is the risk of heart attack in patients labeled as having the metabolic syndrome greater than the risk caused by its constituent factors?  A large study answering this question has just been reported in Journal of the American College of Cardiology.

The INTERHEART study is international in scope – there are centers in 52 countries.  Data from almost 27,000 participants were use; they were grouped into 12,300 heart attack patients and 14,500 controls.  Two criteria were used to diagnose the metabolic syndrome – the WHO’s and the International Diabetes Federation’s. 

It was found that presence of the metabolic syndrome was accompanied by an increased likelihood of having a heart attack.  This increase was 2.69 times that of the risk in people without the metabolic syndrome, and similar to that for diabetes and high blood pressure (increased odds of 2.72- and 2.60-times, respectively); it was significantly stronger than the odds for abdominal obesity (1.64-times) and low HDL level (1.30-times).

How do we interpret these findings?  The authors of the study say the increased risk of an MI in people with the metabolic syndrome is “generally comparable to that conferred by some, but not all, of its component risk factors”.  They argue that those who support the concept of a metabolic syndrome believe that when the component risk factors occur together this would have a greater effect on risk, and therefore it’s important to identify such patients.  But the findings here disprove that.  Therefore, a diagnosis of metabolic syndrome is not useful; it’s better just to treat the actual risk factor or factors the patient has.  QED – the metabolic syndrome is no longer a useful concept.