Metabolic syndrome independently predicts stroke, all-cause mortality

March 27, 2007

It has been well-established that patients with the metabolic syndrome have twice the risk of cardiovascular (CV) disease and five times the risk of developing type 2 diabetes compared with those without metabolic syndrome. However, controversy exists as to whether the metabolic syndrome has predictive value in terms of CV outcomes beyond that seen with its individual components, said Ajay K. Gupta, MD, during the American Academy of Cardiology's 56th annual scientific session.

It has been well-established that patients with the metabolic syndrome have twice the risk of cardiovascular (CV) disease and five times the risk of developing type 2 diabetes compared with those without metabolic syndrome. However, controversy exists as to whether the metabolic syndrome has predictive value in terms of CV outcomes beyond that seen with its individual components, said Ajay K. Gupta, MD, during the American Academy of Cardiology's 56th annual scientific session.

The components of the metabolic syndrome are elevated fasting blood glucose, elevated triglycerides, low high-density lipoprotein levels, a large waist circumference, and hypertension.

Dr. Gupta analyzed outcomes data for 8091 metabolic syndrome patients included in the ASCOT-BPLA (Anglo-Scandinavian Cardiac Outcomes Trial) study to determine whether metabolic syndrome does in fact have predictive value in CV outcomes. ASCOT-BPLA included 19,257 hypertensive patients with three or more CV risk factors but no coronary artery disease. “We specifically wanted to see if metabolic syndrome is an independent risk factor for CV events beyond the predictive value of hypertension," said Dr. Gupta, International Centre of Circulatory Health, Imperial College, London, UK.

The metabolic syndrome patients were followed for 5.5 years and Dr. Gupta assessed the predictive value of the metabolic syndrome for each of 11 outcome measures, including all-cause mortality, CV mortality, fatal and nonfatal stroke, fatal and nonfatal myocardial infarction, and revascularization procedures.

An unadjusted analysis showed that metabolic syndrome was associated with a statistically significant increased risk of coronary disease outcomes, but not for other CV outcomes, such as stroke. However, when adjusted for age, sex, and ethnicity, metabolic syndrome became a stronger predictor of coronary disease outcomes and also was predictive for stroke and all-cause mortality, Dr. Gupta said.

“When we then adjusted the data for individual metabolic syndrome components the prediction of metabolic syndrome for CV outcomes became weaker and insignificant," he said. “However, metabolic syndrome remained significantly associated with increased risk of stroke and all-cause mortality."

Dr. Gupta noted that the analysis might have been limited because body mass index measurements were used instead of waist circumference, but he added that the strengths of the study included the large number of patients, as well as the large number of events that occurred in ASCOT-BPLA.