How do we account for racial differences in medical outcomes?

An interesting article was recently published in the Annals of Internal Medicine, the journal of the American College of Physicians (my professional organization). It has been noted in previous studies that there are differences in outcomes between African Americans and whites who are diagnosed with a heart attack. What hasn't been clear is the reason for these differences.

There are known disparities in access to health care, and there is sometimes a stated distrust in the medical system by minorities (not just due to such atrocities as the Tuskegee Syphilis Study). Many of us who practice clinical medicine have had to work hard to earn the trust of our minority patients. There are also significant differences in health risks in self-indentified blacks and whites. Do these explain the extent of health disparities? In documenting disparities we only identify the problem; if we don't know why blacks and whites have different outcomes, we cannot move forward to improve care.

This study is a prospective cohort study. White and black patients who had myocardial infarctions and survived were enrolled and followed over the course of about two years. The study focused on how people felt, and on clinical factors such as re-hospitalization.

Mortality rates at two years were significantly higher for blacks (19.9% for black patients versus 9.3% for white patients; crude hazard ratio (HR) 2.31 (CI, 1.77 to 3.00)). Blacks were not more likely to be re-hospitalized (a surrogate measure of outcome and health), but were significantly more likely to experience chest pain and reported a decreased quality of life compared to white patients.

But here comes the interesting part:

In general, the outcome differences between black and white patients were most attenuated by adjusting for patient characteristics present before admission (such as socioeconomic status and comorbid conditions) and were only marginally affected by adjusting for differences in treatment. Our findings suggest that racial disparities in outcome are associated with a myriad of racial differences in risk factors for adverse outcomes and that focusing on the processes of care for myocardial infarction may not be the most effective strategy for achieving equity in outcomes.

In other words, most of the differences in black and white patients were not due to disparities in their hospital care but in their overall health and socioeconomic status.

This has profound implications regarding health care inequality in the U.S. If these data are accurate, independent of how we treat people in the hospital during a heart attack, a patient's position in society, and to some extent their other ethnically-linked health problems, predict outcomes. This implies that health care inequalities have a significant societal component independent of how patients are treated in the hospital. Disparities in class may be more significant than disparities in treatment.

This certainly makes sense. Those who are poor have less access to insurance, medication, and frequent medical follow up care.

I may be beating a dead horse here, but universal coverage may be one big step toward eliminating racial disparities in our health care system.

John A. Spertus, MD, MPH; Philip G. Jones, MS; Frederick A. Masoudi, MD, MSPH; John S. Rumsfeld, MD, PhD; and Harlan M. Krumholz, MD, SM (2009). Factors Associated With Racial Differences in Myocardial Infarction Outcomes Annals of Internal Medicine, 150 (5), 314-324 PMID: 19258559