Race and gender disparities in rates of cardiac revascularization: do they reflect appropriate use of procedures or problems in quality of care?

BACKGROUND: Numerous studies have documented substantial differences by race and gender in the use of coronary artery bypass graft surgery and percutaneous coronary angioplasty. However, few studies have examined whether these differences reflect problems in quality of care.

METHOD: We selected a random sample stratified by gender, race, and income of 5026 Medicare beneficiaries aged 65 to 75 who underwent inpatient coronary angiography during 1991 to 1992 in 1 of 5 states. We compared the frequency of 2 problems in quality by race and gender: underuse or the failure to receive a clinically indicated revascularization procedure and receipt of revascularization when it was not clinically indicated. We used 2 independent sets of criteria developed by the RAND Corporation and the American College of Cardiology/American Hospital Association (ACC/AHA). We also examined survival of the cohort through March 31, 1994.

RESULTS: Revascularization procedures were clinically indicated more frequently among whites than blacks and among men than women. Failure to receive revascularization when it was indicated was more common among blacks than among whites (40% vs. 23-24%, depending on the criteria, both P<0.001) but similar among men and women (25% vs. 22-24%, P>0.05). Racial disparities remained similar after adjusting for patient and hospital characteristics. Among patients rated inappropriate, use of procedures was greater for whites than blacks using RAND criteria (10.5% vs. 5.8%, P<0.01) and greater for men than for women (14.2% vs. 5.3% by RAND criteria, P=0.001; 8.2% vs. 4.0%% by ACC/AHA criteria, P=0.04). After multivariate adjustment, the disparities for race and gender remained similar and were statistically significant using RAND criteria. Mortality rates tended to validate our appropriateness criteria for underuse.

CONCLUSIONS: Racial differences in procedure use reflect higher rates of clinical appropriateness among whites, greater underuse among blacks, and more frequent revascularization when it was not clinically indicated among whites. Underuse is associated with higher mortality. In contrast, men had higher rates of clinical appropriateness and were more likely to receive revascularization when it was not clinically indicated. There was no evidence of greater underuse among women.