Racial variation in the use of coronary-revascularization procedures: Are the differences real? Do they matter?

Background: Studies have reported that blacks undergo fewer coronary- revascularization procedures than whites, but it is not clear whether the clinical characteristics of the patients account for these differences or whether they indicate underuse of the procedures in blacks or overuse in whites. Methods: In a study at Duke University of 12,402 patients (10.3 percent of whom were black) with coronary disease, we calculated unadjusted and adjusted rates of angioplasty and bypass surgery in blacks and whites after cardiac catheterization. We also examined patterns of treatment after stratifying the patients according to the severity of disease, angina status, and estimated survival benefit due to revascularization. Finally, we compared five-year survival rates in blacks and whites. Results: After adjustment for the severity of disease and other characteristics, blacks were 13 percent less likely than whites to undergo angioplasty and 32 percent less likely to undergo bypass surgery. The adjusted black:white odds ratios for receiving these procedures were 0.87 (95 percent confidence interval, 0.73 to 1.03) and 0.68 (95 percent confidence interval, 0.56 to 0.82), respectively. The racial differences in rates of bypass surgery persisted among those with severe anginal symptoms (31 percent of blacks underwent surgery, vs. 45 percent of whites; P<0.001) and among those predicted to have the greatest survival benefit from revascularization (42 percent vs, 61 percent, P<0.001). Finally, unadjusted and adjusted rates of survival for five years were significantly lower in blacks than in whites. Conclusions: Blacks with coronary disease were significantly less likely than whites to undergo coronary revascularization, particularly bypass surgery - a difference that could not be explained by the clinical features of their disease. The differences in treatment were most pronounced among those predicted to benefit the most from revascularization. Since these differences also correlated with a lower survival rate in blacks, we conclude that coronary revascularization appears to be underused in blacks.