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

Abstract

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.

Keywords: Atherogenic dyslipidemia; EUROASPIRE; Fatal vascular events; Hypertriglyceridemic waist; Pre-diabetes; Secondary prevention.