Metabolic Syndrome: A Misleading ‘Diagnosis’

Joint European/ADA Paper Asks for Clearer Definition, More Research

Two major health organizations in Europe and the United States are calling for closer examination of a syndrome that has been widely believed to predict the risk of developing heart disease, questioning whether it has been appropriately defined and whether it is in fact a syndrome at all.
In a joint paper published in the September issue of Diabetes Care and Diabetologia, the American Diabetes Association and European Association for the Study of Diabetes (EASD) argue that the
metabolic syndrome – which has come to be regarded as a predictor of cardiovascular disease – is poorly defined, inconsistently used and in need of further research to help understand whether and how it should be treated. Doctors, the authors warn, should not be diagnosing people with this “syndrome” or attempting to treat it as a separate malady until the science behind it is clear.

“We shouldn’t be diagnosing people with the ‘metabolic syndrome.’ Doing so misleads the patient into believing he or she has some kind of disease. What they really have is a cluster of cardiovascular risk factors. In many cases, the combination of risk factors may not add up to a more significant or higher cardiovascular risk than the individual components,” according to Richard Kahn, PhD, Chief Scientific and Medical Officer, American Diabetes Association.

The metabolic syndrome is often defined as having any three or more of the following: a large waist circumference; high triglyceride levels; high blood pressure; low HDL (“good”) cholesterol; and high blood glucose levels. The World Health Organization offers a slightly different definition, including anyone who has diabetes or insulin resistance and two of the following: high waist-to-hip ratio; high
triglycerides or low HDL cholesterol; high blood pressure; and a high urinary albumin excretion rate.
Taken individually, each of the above conditions is considered a risk factor for cardiovascular disease and should be treated as such, the authors state. “But there is no magical combination of risk factors that further boosts a person’s cardiovascular risk or constitutes a separate disease,” said Ele Ferrannini, MD, President, European Association for the Study of Diabetes.

The definitions don’t even agree upon how low HDL should be to be considered “low” or how high blood pressure should be to be considered “high,” the authors note. Consequently, studies showing a correlation between a combination of these factors and the risk of developing heart disease are highly inconsistent.

“The metabolic syndrome requires much more study before its designation as a “syndrome” is truly warranted and before its clinical utility is adequately defined,” the authors wrote in their conclusion.
In the meantime, the paper recommends that doctors continue to evaluate patients for the presence of other cardiovascular risk factors when one is discovered; aggressively treat individual cardiovascular risk factors; avoid labeling patients with the term “metabolic syndrome;” and not attempt to prescribe a treatment for this “syndrome” until new, solid evidence is obtained.

The metabolic syndrome: time for a critical appraisal
Joint statement from the American Diabetes Association
and the European Association for the Study of Diabetes
R. Kahn, J. Buse, E. Ferrannini and M. Stern
Diabetes Care 28:2289-2304, 2005