Some defend metabolic syndrome's clinical value

Washington -- A debate over the usefulness of the constellation of conditions known as metabolic syndrome in predicting disease shows no sign of abating.

The American Assn. of Clinical Endocrinologists and the American College of Endocrinology released a statement Oct. 14 reaffirming their belief that the syndrome, which they call insulin-resistance syndrome, remains a clinically useful tool.

Questions concerning the syndrome's value were raised in late August by the American Diabetes Assn. and its European counterpart, triggering an investigation by the endocrinologists into the science behind a decision they made two years earlier to publish a definition of the syndrome.

They determined that the science was solid. "There is nothing we said then that is not correct," said Yehuda Handelsman, MD, a co-chair of the AACE panel that drafted the initial statement and a member of the team from AACE/ACE that reviewed it.

The debate raises the question of what to do about the 47 million Americans who are overweight, have hypertension and high triglyceride and fasting glucose levels. Many physicians believe that this cluster of risk factors, known as metabolic syndrome, is particularly important in predicting which patients will develop diabetes or cardiovascular disease.

Metabolic syndrome is also credited by many with getting patients to pay heed to the importance of weight loss and increased physical activity in maintaining health.

Some not so sure

But Richard Kahn, PhD, chief scientific and medical officer of the American Diabetes Assn. and a lead author of the ADA paper, remains unconvinced of the usefulness of the syndrome as a diagnostic tool.

"The fundamental question here is: What is the value of putting that label on someone?"

Instead, Dr. Kahn recommends that physicians treat the individual risk factors aggressively. He and his colleagues wrote in the September issues of Diabetes Care and Diabetologia that there is no solid evidence that any of the metabolic syndrome health factors contribute more together than they do individually.

But Daniel Einhorn, MD, a California clinician who also co-chaired the AACE panel and reviewed the position statement, said grouping the risk factors together had made an important contribution to his practice. "We do know that it is clinically useful to think of it as a syndrome, to target insulin resistance, and to educate our patients and communities about this clustering of risk factors."

Although metabolic syndrome and insulin-resistance syndrome describe nearly the same conditions, there are a few differences. "Insulin resistance is broader in scope. It includes women with infertility issues like polycystic ovarian syndrome and fatty liver disease," Dr. Handelsman said.

Dr. Einhorn acknowledged that there is some ambiguity surrounding the AACE-defined syndrome. "We are not certain what links all parts of the cluster, and we don't know whether insulin resistance will prove to be the ultimate cause."

Meanwhile, the ADA is working to establish common ground with the American Heart Assn. on metabolic syndrome's diagnostic value. The AHA believes that the syndrome is useful to determine which patients are at risk for heart disease beyond looking for high LDL levels.

The groups plan to collaborate on a paper, to appear together at conferences to talk about metabolic syndrome and to support additional research, Dr. Kahn said. They are expected to focus on the importance of weight loss and other lifestyle changes for healthy living, he said.

The endocrinologists also are willing to alter their position statement if and when new evidence is presented, Dr. Einhorn said.

"The AACE and ACE hope that healthy debate will not be misconstrued as fractious controversy and that further research in this field will clarify the remaining areas of uncertainty," the groups noted in their statement.