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How deadly is the "deadly quartet"? A post-CABG evaluation
1Department of Cardiology, The Cleveland Clinic Foundation, Ohio 44195, USA. sprechd@ccf.org
Insights
Metabolic risk factors significantly increase mortality after coronary artery bypass surgery (CABG). Clustering of these factors, especially in women, predicts poorer survival even after revascularization.
Area of Science:
- Cardiovascular Surgery
- Metabolic Syndrome
- Clinical Outcomes Research
Background:
- The
- deadly quartet
- (obesity, diabetes, hypertension, hypertriglyceridemia) is linked to coronary heart disease.
- Its impact on survival post-coronary artery bypass surgery (CABG), particularly by gender, is not well-established.
Purpose of the Study:
- To assess the predictive value of clustered metabolic risk factors for mortality after CABG.
- To investigate the influence of gender on the relationship between metabolic risk clusters and survival.
Main Methods:
- Analysis of 6,428 patients undergoing primary isolated CABG (1987-1992) with median 8-year follow-up.
- Cox models evaluated all-cause mortality, incorporating metabolic risk factors as a sum (0-4).
- Examined gender differences in survival related to metabolic risk clusters.
Main Results:
- Increased number of metabolic risk factors significantly correlated with higher mortality (HR 1.64 for 1 factor to 3.95 for 4 factors).
- Annualized mortality rose from 1% (no risk factors) to 3.3% (all four risk factors).
- Hazard ratios for four risk factors were 2.58 in men and 13.39 in women; observed risk factor clustering was higher in women (21%) than men (10%).
Conclusions:
- Metabolic risk factor clustering occurs more than expected by chance, particularly in women.
- Survival is reduced in patients with clustered metabolic risk factors, even after CABG revascularization.
Objectives:
The aim of the study was to determine the value of a cluster of metabolic risk factors in predicting mortality after coronary artery bypass surgery (CABG).
Background:
The "deadly quartet" of metabolic risk factors (i.e., obesity, diabetes, hypertension, and hypertriglyceridemia) has been associated with coronary heart disease in healthy population studies. The expected influence of the cluster on survival in secondary prevention remains untested overall as well as by gender.
Methods:
Patients with lipid profiles undergoing primary isolated CABG (n = 6,428) between 1987 and 1992 were followed a median of eight years. Cox models were used to evaluate all-cause mortality. Metabolic risk factors were incorporated as the sum of deadly quartet risk factors present in each patient (0 to 4). The role of gender as it relates to survival and metabolic risk clusters was also examined.
Results:
The sum of deadly quartet risk factors showed a significant relationship to mortality as the hazard ratio increased from 1.64 (confidence interval [CI] = 1.34-2.01) for one risk factor to 3.95 (2.73-5.69) for four risk factors. Annualized mortality ranged from 1% per year in patients with no risk factors to 3.3% per year in patients with all four risk factors. Within gender, the hazard ratio associated with four risk factors was 2.58 for men and 13.39 for women. The expected clustering of risk factors was 8% compared to the observed clustering of 10% in men and 21% in women.
Conclusions:
This cohort showed risk factor clustering beyond that expected due to chance, particularly in women. Even after revascularization, survival is diminished for patients with members of a family of metabolic risk factors at the time of surgery.