Understanding racial variation in the use of coronary revascularization procedures - The role of clinical factors

Background: Black patients undergo coronary artery bypass grafting and perc utaneous transluminal coronary angioplasty less often than white patients. It is unclear how racial differences in clinical factors contribute to this variation. Methods: A retrospective cohort study was performed of 666 male patients (3 26 blacks and 340 whites), admitted to 1 of 6 Veterans Affairs hospitals fr om October 1, 1989, to September 30, 1995, with acute myocardial infarction or unstable angina who underwent cardiac catheterization. The primary comp arison was whether racial differences in percutaneous transluminal coronary angioplasty and coronary artery bypass grafting rates persisted after stra tifying by clinical appropriateness of the procedure, measured by the appro priateness scale developed by the RAND Corporation, Santa Monica, Calif. Results: Whites more often than blacks underwent a revascularization proced ure (47% vs 28%). There was substantial variation in black-white odds ratio s within differ ent appropriateness categories. Blacks were significantly l ess likely to undergo percutaneous transluminal coronary angioplasty (odds ratio, 0.30; 95% confidence interval, 0.14-0.63 [P<.01]) when the indicatio n was rated "equivocal." Similarly, blacks were less likely to undergo coro nary artery bypass grafting (odds ratio, 0.44; 95% confidence interval, 0.2 3-0.86 [P<.01]) when only coronary artery bypass grafting was indicated as "appropriate and necessary." Differences in comorbidity or use of cigarette s or alcohol did nor explain these variations. Using administrative data fr om the Veterans Health Administration, we found no differences in 1-year (5 .2% vs 7.4%) and 5-year (23.3% vs 26.2%) mortality for blacks vs whites. Conclusion: Among patients with acute myocardial infarction or unstable ang ina, variation in clinical factors using RAND appropriateness criteria for procedures explained some, but not all, racial differences in coronary reva scularization use.