There is no reason to cluster the five or more risk factors for heart disease into a syndrome, say two leading diabetes organizations. There is no particular combination that increases an individual's odds of getting heart disease.

The metabolic syndrome has come to be regarded by most cardiologists, diabetologists and researchers as a strong predictor of heart disease, requiring treatment with multiple drugs. But the world's two leading diabetes organizations recently issued a joint statement announcing that metabolic syndrome has never been "appropriately defined."

Within weeks, two heart organizations issued treatment guidelines for metabolic syndrome, signaling that the condition does, in fact, exist. Confused? Read on and become more so.

Not a Separate Malady

Metabolic syndrome, also known as "Syndrome X," is a cluster of known risk factors for heart disease. The diagnosis is applied to people with three or more of the following: a large waist circumference, high triglyceride levels, high blood pressure, insulin resistance, and low levels of high-density lipoproteins, or HDL, the so-called "good" cholesterol.

It has been estimated that one in six Americans over age 50 qualify for a metabolic syndrome diagnosis.

Metabolic syndrome "took hold," according to the joint statement, when several august organizations like the World Health Organization and the US National Cholesterol Education Program gave official recognition to the "disorder." Interestingly, each organization had differing definitions for the condition.

The American Diabetes Association and the European Association for the Study of Diabetes issued their joint statement identifying metabolic syndrome as "a misleading 'diagnosis'" in the September 2005 issues of Diabetes Care and Diabetologia, respectively. The statement is based on a review of all available evidence about issues related to metabolic syndrome.

Both organizations warned doctors that they "should not be diagnosing people with this 'syndrome' or attempting to treat it as a separate malady until the science behind it is clear." For their review, Dr. Kahn and colleagues examined the evidence for the definition of metabolic syndrome and its purported association with heart disease.

The reviewers found no reason to cluster the five or more risk factors for heart disease into a syndrome. There is no particular combination that increases an individual's odds of getting heart disease.

"Instead, each risk factor should be dealt with independently of the others, said the lead author, Richard Kahn, PhD, in a telephone interview. Dr. Kahn is the Chief Scientific and Medical Officer at the American Diabetes Association.

Industry's Role?

Another problem with metabolic syndrome, explained Dr. Kahn, is the enormous range identified for each risk factor included in the definition of metabolic syndrome.

"One person could have a blood glucose level of 100, and another could have a glucose level of 300," he said, "Yet they would both be in the same category." And he is concerned about the psychological impact on people who have been told that they have a separate disease, "which it is not."

No sooner had the joint statement been sent to the media than two heart organizations announced new guidelines to help doctors diagnose and treat metabolic syndrome. They came from the American Heart Association and the National Heart, Lung, and Blood Institute.

Dr. Kahn does not see this as a reaction to the recently published joint statement. "The guidelines were clearly in the pipeline well before our joint statement, but we hope that our statement will spur more discussion with the heart people."

Asked about industry's role in spreading the word about metabolic syndrome, Dr. Kahn responded, "There are companies in the pharmaceutical world that encouraged, promulgated, and supported the diagnosis of metabolic syndrome."