Metabolic syndrome useful predictor for CVD risk
Older age increased this predictive value.
Metabolic syndrome is associated with a significant risk for cardiovascular disease.
Previous research has found that metabolic syndrome increases the risk for CVD and diabetes. Researchers at the University of Texas Health Science Center at San Antonio have conducted a study to examine whether the varying National Cholesterol Education Program-Adult Treatment Panel-III, International Diabetes Federation and World Health Organization definitions of metabolic syndrome were predictors for CVD and diabetes in the San Antonio Heart Study.
Predicting the risk
Carlos Lorenzo, MD, assistant professor, department of medicine, division of clinical epidemiology at the University of Texas, and colleagues compared metabolic syndrome with the current standards for predicting coronrary heart disease (National Cholesterol Education Program risk factor categories) and diabetes (OGTT).
Age in particular was examined. “We took into account the higher CVD risk of men aged >45 years and women aged >55 years and hypothesized that metabolic syndrome plus age >45/>55 years in men/women would be a good CVD marker,” the researchers wrote in Diabetes Care.
The investigators also hypothesized that impaired fasting glucose and metabolic syndrome combined would be a better predictor of diabetes than either factor alone.
They used a cohort from San Antonio Heart Study (n=2,559; age range, 25 to 64 years; follow-up, 7.4 years). Patients in the SAHS study were assessed once in the 1980s and again in the 1990s. All were extensively interviewed, their waist circumference and BP were measured and plasma glucose and serum lipids were analyzed after fasting.
Prediction of CVD
No one definition of metabolic syndrome predicted the risk for CVD better than another, according to Lorenzo.
The ATP-III (OR 2.00; 95% CI, 1.33-3.01), IDF (OR 1.69; 95% CI, 1.13-2.54) and WHO (OR 1.73; 95% CI, 1.12-2.67) definitions predicted CVD risk independently of age, sex, ethnic origin, history of CVD and type 2 diabetes, non-HDL cholesterol, smoking status and family history of myocardial infarction.
“This is not surprising since individual components are major CVD risk factors,” the researchers wrote. “However, increased risk associated with a marker is not equivalent to adequate performance of a marker for predicting risk for persons. The IDF definition tended to have higher sensitivity and lower specificity than the other two definitions.”
In patients with a history of CVD or diabetes, metabolic syndrome did not predict new CVD events. “Nevertheless, metabolic syndrome may be a less relevant concept in these individuals because all modifiable risk factors require aggressive treatment,” they wrote.
Age as a predictor
Older age (above the researcher’s cutoffs) increased the ability of metabolic syndrome to predict CVD.
In men, the CVD risk of metabolic syndrome plus age >45 years was comparable to the presence of multiple risk factors plus a 10-year CHD risk of 10% to 20%.
The researchers said that men with metabolic syndrome aged 45 years or older may be eligible for therapy.
In women, the predictive discrimination of the metabolic syndrome plus age >55 was also statistically significant, but less reliable (wide confidence intervals) because of their lower CVD risk. CVD risk of metabolic syndrome plus age >55 was similar to that of 10-year CVD risk of 5% to 20%.
“In older people, it seems that metabolic syndrome is more important because they are at higher risk for CVD. The increased risk means that we should treat metabolic syndrome or consider that patient at a significantly higher risk,” Lorenzo told Endocrine Today.
According to Lorenzo, “The message of this [study] is that we know the risk associated with each of the CV risk factors, diabetes, cholesterol and so on, but sometimes we might overlook patients who are borderline. But metabolic syndrome tells us that when you have several of these conditions at the same time, you might not be a little more at risk for CVD, but at significant risk.” –by Katie Kalvaitis
For more information:
- Lorenzo C, Williams K, Hunt K, Haffner S. The National Cholesterol Education Program-Adult Treatment Panel III, International Diabetes Federation and World Health Organization definitions of the metabolic syndrome as predictors of incident cardiovascular disease and diabetes. Diabetes Care. 2007;30:8-13.