How deadly is the “deadly quartet”?: A post-CABG evaluation

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.