Prospective study of metabolic syndrome as a mortality marker in chronic coronary heart disease patients.

BACKGROUND

We aimed to clarify the impact of metabolic syndrome (MetS) as assessed by different definitions on the cardiovascular mortality in patients with coronary heart disease (CHD).

METHODS

A total of 1692 patients, 6-24months after myocardial infarction and/or coronary revascularization at baseline, were followed in a prospective cohort study. MetS was identified using four different definitions: standard National Cholesterol Education Program definition (NCEP-ATPIII) based on the presence of ≥3 of the following factors: increased waist circumference, raised blood pressure, hypetriglyceridemia, low high-density lipoprotein cholesterol, and increased fasting glycemia; modified NCEP-ATPIII definition (similar, but omitting antihypertensive treatment as an alternative criterion); presence of "atherogenic dyslipidemia"; or "hypertriglyceridemic waist". The primary outcome was a fatal cardiovascular event at 5years.

RESULTS

During 5-year follow-up, 117 patients (6.9%) died from a cardiovascular cause. Patients with MetS by modified NCEP-ATPIII (n=1066, 63.0% of the whole sample) had significantly higher 5-year cardiovascular mortality [adjusted hazard risk ratio (HRR) 2.01 [95%CI:1.26-3.22]; p=0.003] than subjects without MetS. However, when testing single MetS component factors, the majority of attributable mortality risk was driven by increased fasting glycemia (≥5.6mmol/L) [HRR 2.69 (95%CI:1.29-5.62), p=0.009] and the significance of MetS disappeared. None of the other MetS definitions, i.e., standard NCEP-ATPIII (n=1210; 71.5%), "hypertriglyceridemic waist" (n=455; 26.9%) or "atherogenic dyslipidemia" (n=223; 13.2%) were associated with any significant mortality risk.

CONCLUSIONS

The co-incidence of MetS has a limited mortality impact in CHD patients, while an increase in fasting glycemia seems to be more a specific marker of mortality risk.