Table 1.

Demographics and Clinical Characteristics of Patients, Stratified by Hospital Tertile of Mortality

Variable	Low Mortality (N=15842)	Medium Mortality (N=14181)	High Mortality (N=15881)	p value
Demographics
Age (yr), median	66.00	66.00	66.00	1.000
Male sex (%)	70.5%	69.1%	68.2%	< 0.001
Non-white race (%)	3.5%	4.3%	5.8%	< 0.001
Risk Factors
Diabetes mellitus (%)	36.2%	39.3%	38.0%	< 0.001
Dialysis (%)	2.2%	2.1%	3.2%	< 0.001
Hypertension (%)	81.7%	84.6%	86.0%	< 0.001
Chronic lung disease
None	81.3%	76.8%	77.7%
Mild	11.3%	14.4%	13.9%	< 0.001
Moderate	4.8%	4.7%	5.1%
Severe	2.5%	4.2%	3.3%
Immunosuppressive therapy (%)	2.3%	2.6%	4.6%	< 0.001
Peripheral vascular disease (%)	14.5%	15.4%	16.9%	< 0.001
Prior cerebrovascular accident (%)	13.3%	15.3%	16.1%	< 0.001
Previous Cardiovascular Interventions
Previous CABG (%)	5.0%	4.5%	5.0%	0.080
Previous valve surgery (%)	2.1%	0.9%	1.7%	< 0.001
Previous PCI (%)	22.3%	24.5%	25.0%	< 0.001
Preoperative Cardiac Status
Previous myocardial infarction (%)	39.4%	45.1%	43.2%	< 0.001
Congestive heart failure (%)
NYHA Class I-III	12.0%	11.4%	13.0%	< 0.001
NYHA Class IV	6.8%	4.3%	7.4%	<0.001
Hemodynamics and Catheterization data
Three vessel coronary disease (%)	61.9%	64.9%	64.5%	< 0.001
Ejection fraction (%), mean	51.8	51.0	51.4	< 0.001
Operative Characteristics
First cardiovascular surgery (%)	93.3%	94.7%	93.6%	< 0.001
Elective status (%)	45.4%	38.7%	44.6%	< 0.001
Procedure
Isolated CABG (%)	70.7%	79.9%	77.7%	< 0.001
Isolated valve surgery (%)	16.6%	10.5%	12.6%	< 0.001
CABG plus valve surgery (%)	12.8%	9.7%	9.7%	< 0.001
Mortality
Expected mortality (%)	2.82	2.88	3.11	< 0.001
Observed-to-expected ratio	0.23–0.77	0.78–0.96	0.97–1.56	-

CABG=coronary artery bypass graft, PCI=previous cardiovascular intervention, MI=myocardial infarction, NYHA=New York Heart Association, CPR=cardiopulmonary resuscitation