Wenneker MB, Epstein AM.
Racial inequalities in the use of procedures for patients with ischemic heart disease in Massachusetts.
JAMA 1989:261(2):253-7.

The purpose of this study was to replicate and improve upon previous research that indicated there may be racial differences in the use of cardiac procedures. Data were obtained from the Massachusetts Health Data Consortium. Patients aged 30-89 years discharged from Massachusetts hospitals in FY1985 who might be appropriate candidates for coronary procedures (those with a principle diagnosis of a disease of the circulatory system or chest pain) or who underwent coronary procedures (including coronary arteriography, coronary artery bypass graft surgery, and coronary angioplasty) were included. The article did not note how patients with repeat admissions were handled in the analyses.

The primary analyses were (Massachusetts) population-based. These analyses showed that black and white patients were roughly equally likely to be admitted for any circulatory disease/chest pain or for ischemic heart disease (age and sex adjusted ratios of white to black rates = 0.95 and 1.19, respectively, significance tests not shown). However, whites were more likely to undergo cardiac catheterization (adjusted white/black RR=1.36), coronary artery bypass surgery (adjusted white/black RR=2.26), and angioplasty (adjusted white/black RR=2.52) (significance tests not shown).

In order to determine whether the observed racial disparities in the use of cardiac procedures were explained by disparities in obtaining hospital admission, analyses were repeated among hospitalized patients with diagnoses of circulatory disease or chest pain. There were racial differences in potential confounding factors. In comparison to whites, blacks were younger, more often female, had a lower income, and were more likely to be uninsured or covered by Medicaid. Additionally, blacks were more likely to be admitted on an emergency basis, and there were significant racial differences in discharge diagnoses (blacks were more likely to have a chest pain diagnosis and less likely to have unstable angina, myocardial infarction, and chronic ischemia). Controlling for each of the above listed confounding factors, blacks were less likely to undergo coronary angiography, coronary bypass, and angioplasty than whites. The only adjusted comparison which did not result in a significant racial difference was the use of angioplasty after adjusting for diagnosis (OR=1.42, 95% confidence interval = 0.80 to 2.54).

When all of the above factors were controlled simultaneously, the racial differences remained significant for coronary artery bypass grafting (OR=1.89, 95% confidence interval=1.30 to 2.74) and angiography (OR=1.29, 95% confidence interval=1.07 to 1.56). Although 70% more whites than blacks underwent angioplasty, this difference was not statistically significant (95% confidence interval=0.94 to 3.07). Other factors that significantly predicted use of these procedures were insurance type, diagnosis, emergency versus elective admission, income, number of secondary diagnoses, and sex (for angiography and coronary artery bypass grafting only).

The authors conclude that the racial differences in the use of cardiac procedures reported both in previous studies and in the current analysis are “not merely a function of diminished physician contact or lower disease recognition,” as the racial patterns were evident even among the cohort of hospitalized patients. However, they note that “these differences may not be due entirely to race per se; they may be due in part to differences in income or disease severity that have not been adequately accounted for in this study.” The explanations the authors consider are as follows: whites may be more severely ill; whites may have greater access to expensive types of care; blacks and whites may differ with regard to preferences toward the sort of care they receive; and (lastly) there may be “differences in care provided, perhaps unintentionally, on the basis of race.” The authors emphasize, “Clearly sociocultural factors influence physician and patient decision making.” The authors note that “it would be unwise to conclude from this study that black patients are underserved or directly harmed by undergoing fewer procedures. Higher procedure rates among white patients may be attributable to overutilization.”