TUESDAY, Jan. 23, 2007 (HealthDay News) -- A cluster of cardiac factors known as "metabolic syndrome" is a strong indicator of increased risk of heart disease, an exhaustive review of the literature concludes.
Metabolic syndrome includes factors such as lower-abdomen obesity, high blood pressure, blood fat disorders such as high LDL ("bad") cholesterol, and insulin resistance or elevated blood sugar levels. Generally, someone with three or more of these factors is said to have metabolic syndrome.
"The question has been for a number of years what the risk associated with metabolic syndrome is," said study author Dr. Apoor S. Gami, an assistant professor of medicine at the Mayo Clinic College of Medicine. "What is the quantified risk in patients with metabolic syndrome? That is one question we could answer by meta-analysis."
A meta-analysis crunches data from a host of prior studies to come to a more solid conclusion. This analysis of 37 studies included more than 170,000 individuals. Gami and his colleagues not only analyzed published studies, but also sought more detailed information from the researchers who did the studies.
The meta-analysis found the risk of heart attack or death was 78 percent higher for people with metabolic syndrome than those who did not have this constellation of risk factors.
"The main take-away from this study is that people identified with metabolic syndrome, regardless of the criteria used to describe metabolic syndrome, are at increased risk of cardiac events or death," Gami said. "There is anywhere from a 50 percent to 200 percent increase in risk, which seems to be stronger in women."
The findings will be published in the Jan. 30 issue of the Journal of the American College of Cardiology.
The implication for medical practice is that anyone with metabolic syndrome needs extra attention for preventive measures, Gami said.
The finding comes as something less than a surprise, said Dr. Robert Eckel, a professor of medicine at the University of Colorado and immediate past president of the American Heart Association.
"Many of us in the field have felt that it [metabolic syndrome] is important for some time now," Eckel said. "There is not anything surprisingly new about this meta-analysis."
But there is ongoing debate about "how you define metabolic syndrome in terms of threshold values," he said. "This is a syndrome, not a disease. We still need to learn more about its components and how we can define them better."
While Eckel said the new study provides "additional evidence for the value of metabolic syndrome," a dissenting view came from Dr. Michael Stern, a professor of medicine at the University of Texas Health Science Center at San Antonio, who has written skeptical reports on the importance of metabolic syndrome, including one for the American Diabetes Association.
"There is no doubt that metabolic syndrome is associated with increased cardiovascular risk," Stern said. "The question is whether it is the best way to identify that risk. There are other established methods of identifying high-risk individuals that are not related to metabolic syndrome."
According to Stern, an equation derived from the long-running Framingham Heart Study provides a better risk assessment than the metabolic syndrome, which is "an arbitrary collection of risk factors. If the goal is to identify high-risk individuals, you can do just as well or better with the Framingham equation."
But the presence of the metabolic syndrome provides better evidence of risk than taking individual components of the syndrome one by one, Gami countered. "Three studies addressed this, and the risk was increased by 50 percent above those of the individual risk factors that were present," he said.
There's more on the metabolic syndrome at the American Heart Association.