"Our study found that the metabolic syndrome is a predictor of significant cardiovascular risk," said Oscar C. Marroquin, M.D., from the Cardiovascular Institute at the University of Pittsburgh School of Medicine and principal investigator in the study. "However, the influence of metabolic status on cardiovascular risk appears to depend on the presence or absence of CAD at study entry. In women with angiographically significant CAD at study entry, the metabolic syndrome significantly increases the risk of adverse cardiovascular outcomes similar in magnitude to the effect of diabetes. No such effect is seen in women without angiographically significant CAD at study entry."
People with three or more of the following criteria are classified as having metabolic syndrome: waist circumference greater than 35 inches for women, fasting triglycerides greater than 150mg/dl, HDL cholesterol less than 50mg/dl in women, hypertension (blood pressure >130/85 mm Hg, and fasting glucose greater 110mg/dl).
"Women with the metabolic syndrome had a four-year survival rate of 94.3 percent compared to 97.8 percent in women with normal metabolic status and 89.4 percent in those with diabetes. Thus, four-year event-free survival rates in women with the metabolic syndrome were intermediate between those with normal metabolic status and those with diabetes," Dr. Marroquin said.
However, among the subset of women with significant documented CAD, the four-year survival rate of 86.2 percent in women with the metabolic syndrome was nearly identical to the 85.9 percent rate observed in women with diabetes, and was much lower than the survival rate of 96.9 percent observed in women with normal metabolic status. From these data, Dr. Marroquin concluded that the cardiovascular risk in women with significant CAD is substantially elevated by the metabolic syndrome.
The study included 755 women, with a mean age of 58 years, who were referred for coronary angiography to evaluate suspected myocardial ischemia; 25 percent of them had metabolic syndrome at study entry. Each woman underwent evaluation of demographic characteristics and medication use, quantitative coronary angiography and blood sampling for measurement of lipids, glucose, insulin and inflammatory markers. Follow-up for the occurrence of untoward cardiovascular events was obtained by annual telephone and/or mail contact.
The primary clinical outcomes of interest were death or a major adverse cardiovascular event (nonfatal myocardial infarction, stroke, congestive heart failure). The median length of follow-up was 3.5 years among the 715 participants who did not die during four-year follow-up and 1.4 years for the 40 non-surviving participants.
In addition to the University of Pittsburgh, other WISE study centers include the University of Alabama at Birmingham; University of Florida, Gainesville; and Allegheny General Hospital in Pittsburgh.