Background: Black patients with coronary artery disease have a higher mortality rate than white Americans. They also have a higher prevalence of hypertension, diabetes mellitus, and renal disease, which may have an effect on mortality rates. The deleterious effect of these comorbidities may be exacerbated by impaired access to secondary prevention strategies and longitudinal care. Therefore, the presence or absence of comprehensive care as indicated by payer status may then affect survival on surgically treated patients. In this study we examined the role of cardiovascular risk factors and insurance carrier status on early outcomes of coronary artery bypass grafting (CABG) surgery in blacks versus white Americans.
Methods and results: From January 1990 to December 1996, 2776 patients (2003 men, 773 women; mean age 63 +/- 10 years), underwent isolated CABG in a multispecialty practice serving a major metropolitan population. There were 494 (17.8%) black patients and 2282 (82.2%) white patients. The proportion of black patients in each payer category was 17.8% commercial, 14.1% managed care, 52.9% Medicaid, and 19.5% Medicare. The effect of preoperative risk factors, including status of operation (elective, urgent, or emergent), sex, race, redo CABG, presence of renal disease, diabetes mellitus, congestive heart failure, myocardial infarction, the completeness of revascularization, age, and left ventricular ejection fraction were analyzed with the chi 2 test for categorical variables and the Student t test for age and ejection fraction. A multiple logistic regression analysis was performed to assess the effect of all variables on mortality rates simultaneously. Black patients had a higher incidence of diabetes mellitus, hypertension, and renal disease than white patients (P < 0.001). Overall, 30-day mortality rate was 2.5% (58 of 2282) in white patients versus 5.5% (25 of 494) for black patients (P < 0.003). Multivariate analysis showed that only emergency surgery status (OR 3.59, P < 0.01), redo CABG (OR 3.78, P < 0.001), hypertension (OR 2.32, P < 0.03), history of congestive heart failure (OR 2.1, P < 0.004), older age (OR 1.07, P < 0.001), and low ejection fraction (OR 0.98, P < 0.003) correlated with mortality rates. Race and payer status were not significant predictors of death.
Conclusions: These data on CABG surgery in black patients suggest that early death is due to associated risk factors and not due to race or insurance payer status.