Objective: To assess whether rates of coronary revascularization procedures differ between blacks and whites after coronary angiography is performed and to assess the relationship of these rates to hospital characteristics.
Design: A retrospective cohort study using 1987 and 1988 data on hospital claims and characteristics from the Health Care Financing Administration.
Setting: One thousand four hundred twenty-nine acute care hospitals that provide coronary angiography in the United States.
Patients: A national sample of 27,485 Medicare Part A enrollees, aged 65 to 74 years, who underwent inpatient angiography for coronary heart disease in 1987.
Main outcome measure: The adjusted odds of revascularization with either coronary angioplasty or bypass graft surgery within 90 days of angiography for whites relative to blacks, controlling for age, sex, region, Medicaid eligibility, principal diagnosis, comorbid diagnoses, and hospital characteristics of ownership, teaching status, urban/suburban or rural location, and availability of revascularization procedures.
Results: White men and women were significantly more likely than black men and women, respectively, to receive a revascularization procedure after coronary angiography (57% and 50% vs 40% and 34%, both P < .001). The adjusted odds of receiving a revascularization procedure after coronary angiography were 78% higher for whites than blacks (95% confidence interval for odds ratio, 1.56 to 2.03). Statistically significant racial differences in the adjusted odds of receiving a revascularization procedure were present in all types of hospitals except rural hospitals, and these differences did not vary significantly by any of the four hospital characteristics (all P > .20 for interaction terms).
Conclusions: Among Medicare enrollees, whites are more likely than blacks to receive revascularization procedures after coronary angiography. Racial differences of similar magnitude occur in all types of hospitals. These differences may reflect overuse in whites or underuse in blacks, but they are unlikely to reflect access to cardiologists or hospitals that perform revascularization procedures. Potential explanations include unmeasured clinical or socioeconomic factors, differing patient preferences, and racial bias at the hospitals performing angiography.