Boston, MA - A new study has found that the concept of the metabolic syndrome as a whole is not as useful for predicting the risk of cardiovascular mortality in older adults as it is in middle-aged people [1]. Dr Dariush Mozaffarian (Harvard Medical School, Boston, MA) and colleagues report their findings in the May 12, 2008 issue of the Archives of Internal Medicine.

Metabolic syndrome does predict risk among older adults, but the parts are better than the sum.

Mozaffarian told heartwire: "This is the first comprehensive study to look at this issue, and we found that two individual parts of the metabolic syndrome—specifically blood pressure and elevated fasting glucose level—predicted mortality in older adults better than trying to combine them [with the three other criteria] into the metabolic syndrome. We showed that metabolic syndrome does predict risk among older adults, but the parts are better than the sum."

Other studies have previously looked at the parts of the metabolic syndrome and the sum of them in older people but have not compared them together, he noted. "The findings suggest that defining metabolic syndrome in an older adult is not as useful as just focusing on blood pressure and blood glucose and that perhaps older adults should be approached differently," he says.

Mozaffarian and colleagues evaluated the relationship between metabolic syndrome and individual metabolic syndrome criteria—abdominal obesity, high triglyceride levels, low HDL levels, hypertension, and elevated fasting glucose—with mortality between 1989 and 2004 among 4258 adults aged 65 or over participating in the Cardiovascular Health Study. Total, cardiovascular, and noncardiovascular mortality were evaluated, and Cox proportional hazard models were used to estimate the mortality hazard ratio predicted by the metabolic syndrome.

At baseline, 31% of men and 38% of women had metabolic syndrome. During 15 years of follow-up, 2116 deaths occurred. After multivariate adjustment, compared with people without metabolic syndrome, those with it had a 22% higher mortality rate. But higher risk with metabolic syndrome was confined to those with elevated fasting glucose levels/treated diabetes mellitus or hypertension as one of the criteria. People with metabolic syndrome without elevated fasting glucose or hypertension did not have increased risk.

Evaluating metabolic syndrome criteria individually, they found that only hypertension and elevated fasting glucose predicted higher mortality; those with both of these criteria had an 82% higher mortality.

"These findings suggest the limited utility of metabolic syndrome for predicting total or CVD mortality in older adults compared with assessment of fasting glucose and blood pressure alone," they note.

In conclusion, Mozaffarian said he would not normally recommend changing clinical practice on the basis of one study, "and other studies need to be done, but based on these results, our study doesn't support using the metabolic syndrome as a major predictor of mortality in older adults.

"Metabolic syndrome did predict mortality, but it would be better if people just first looked at blood pressure and glucose or diabetes risk and use those two factors for prediction. It does suggest that older adults should be approached differently."

He stressed, however, that this does not mean that other components of the metabolic syndrome should not be treated in individual older patients, where merited.