Purpose: Racial differences in the treatment of patients with myocardial infarction are often presented as nationally consistent patterns of care, despite known regional variations in quality of care. We sought to determine whether racial differences in myocardial infarction treatment vary by U.S. census region.
Methods: We conducted a retrospective analysis of medical record data from 138,938 elderly fee-for-service Medicare beneficiaries hospitalized with myocardial infarction between 1994 and 1996. Patients were evaluated for the use (admission, discharge) of aspirin and beta-blockers, and cardiac procedures (cardiac catheterization, any coronary revascularization) within 60 days of admission.
Results: Nationally, black patients had lower crude rates of aspirin and beta-blocker use, cardiac catheterization, and coronary revascularization than did white patients. Racial differences in treatment, however, varied by region. Black patients in the Northeast had rates of aspirin use that were similar to those of white patients on admission (50.6% vs. 49.8%, P = 0.58) and at discharge (77.5% vs. 74.2%, P = 0.07), whereas racial differences were observed in the South (admission: 43.7% vs. 48.8%, P <0.001; discharge: 69.5% vs. 73.2%, P <0.001), Midwest (admission: 48.4% vs. 52.3%, P = 0.004), and West (admission: 49.2% vs. 56.2%, P <0.001; discharge: 70.7% vs. 76.2%, P = 0.02). Racial differences in beta-blocker use were comparable across regions (admission: P = 0.59, discharge: P = 0.89). There were no differences in cardiac catheterization use among black and white patients in the Northeast (38.9% vs. 40.5%, P = 0.24), as opposed to the Midwest (43.3% vs. 48.9%, P <0.001), South (39.2% vs. 48.5%, P <0.001), and West (38.3% vs. 48.6%, P <0.001). Similarly, racial differences in any coronary revascularization use were smallest in the Northeast (22.1% vs. 26.7%, P <0.001), greater in the Midwest (24.7% vs. 33.5%, P <0.001), and largest in the South (20.7% vs. 32.0%, P <0.001) and West (22.9% vs. 33.7%, P <0.001). Regional variations in racial differences persisted after multivariable adjustment for aspirin on admission (P = 0.09) and any coronary revascularization (P = 0.10).
Conclusion: Racial differences in the use of some therapies for myocardial infarction in patients hospitalized between 1994 and 1996 varied by region, suggesting that national evaluations of racial differences in health care use may obscure potentially important regional variations.