Metabolic syndrome prevalent in heart attack patients

Nearly half of heart attack patients also met criteria for metabolic syndrome, putting them at a higher risk for development of heart failure, according to an article in the May 23 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.

Metabolic syndrome is a group of risk factors in an individual that may precede type 2 diabetes mellitus, according to background information in the article. The definition for metabolic syndrome includes thresholds for waist circumference, concentrations of triglycerides, high-density lipoprotein (HDL) cholesterol (the "good cholesterol"), fasting blood glucose levels, and elevated blood pressure. A survey found that metabolic syndrome was prevalent in 25 percent of white Americans and 44 percent of people 50 years and older. The effect of metabolic syndrome after acute myocardial infarction (AMI, heart attack) has not yet been studied.

Marianne Zeller, Ph.D., from the University of Burgundy, Dijon, France, and colleagues examined the prevalence of metabolic syndrome in 633 patients hospitalized with AMI. Patients were enrolled if they were 18 years or older and were admitted to the hospital within 24 hours of the onset of heart attack symptoms. Participants were diagnosed with metabolic syndrome if they had three of five criteria: a waist circumference greater than 102 cm (40 inches) in men and 88 cm (35 inches) in women, high triglyceride levels, low HDL cholesterol levels, high blood glucose level, and high blood pressure.

The researchers found that 46 percent (n = 290) of patients met the criteria for metabolic syndrome. Patients with metabolic syndrome were older, more likely to be women, had a more frequent history of previous MI than patients without metabolic syndrome, and had a higher number of cardiovascular risk factors. The metabolic syndrome was associated with worse in-hospital outcomes, and an increased risk of heart failure. Examining the metabolic syndrome criteria independently, the researchers found that hyperglycemia (high blood glucose level) was a major determining factor associated with severe heart failure.

"Our study showed the high prevalence of metabolic syndrome among patients with AMI and highlights the detrimental impact of metabolic syndrome on short-term outcomes, particularly heart failure," the authors write. "Finally, our study suggests that, among metabolic syndrome components, hyperglycemia has the strongest relation to increased incidence of congestive heart failure in patients with metabolic syndrome and MI. Given the ever-increasing prevalence of metabolic syndrome worldwide, this finding has important clinical implications and confirms the importance of evaluating glycemic control during the acute phase of MI."