When a patient has a heart attack, clearing blocked arteries and restoring blood flow as quickly as possible can be the difference between life and death. While heart-attack care improved over the past decade, the study found that disparities in the use of medications and diagnostic procedures remained consistent.
The team of investigators from Emory, Yale, and other U.S. institutions studied the records of 598,911 white and black patients treated for heart attacks between 1994 and 2002 at 658 hospitals participating in the National Registry of Myocardial Infarction, sponsored by the Genentech Corporation. They examined differences by sex and race in the use of reperfusion therapy (the use of a drug or invasive catheter procedure to open an artery blocked by a clot); coronary angiography (a diagnostic procedure used to identify blockages in the heart's circulation); aspirin; and beta-blocker therapy. In order to eliminate differences attributable to illness of the patients, they included only patients who were ideal candidates for therapy.
Although observed differences in the use of medications such as aspirin and beta-blockers between white, black, male and female patients became small after accounting for other patient characteristics associated with sex and race, the study found that rates of reperfusion therapy, coronary angiography and in-hospital death after heart attack varied according to race and sex. The rate of treatments went progressively down in white women, black men and black women compared with white men, with black women found to have the lowest use of interventions. For example, black women with the appropriate indications for therapy had 10 percent lower rates of reperfusion therapy and 24 percent lower rates of angiography compared to white men. Black women also had the highest in-hospital mortality rates –– 11 percent higher than white men –– among the four sex and race groups. In contrast, differences in treatment and mortality between white women and white men were generally small.
Although a number of studies have shown disparities in cardiovascular treatment, this study was unique in that the researchers were looking for changes in disparities over time. They were surprised to discover that differences by sex and race were essentially unchanged between 1994 and 2002 and there was no trend toward a lessening of the treatment gaps for women and blacks in recent years.
"Lower rates of treatment in patients who are clinically appropriate for treatment are troubling and raise obvious concerns about under-treatment," said Viola Vaccarino, MD, PhD, associate professor of medicine (cardiology) at Emory University School of Medicine and associate professor of epidemiology at Emory's Rollins School of Public Health and leader of the multi-institutional study. "These differences in treatment are particularly concerning for use of reperfusion therapy and cardiac catheterization because race and sex differences in treatment were not explained by patient age, risk factors or other clinical characteristics that might differ between patients. Simply put, we could not determine the reasons for these differences."
The reasons for the persisting differences may reflect some unmeasured characteristics of the patients or of the healthcare system that have not changed over time, the authors report. For example, women and black patients with heart attacks may have less typical symptoms leading to delayed diagnosis and delayed treatment. The socioeconomic status of the patient may also play a role, perhaps leading to lower access to specialist care, or admission to centers of poorer quality.
Nanette K. Wenger, MD, professor of medicine (cardiology) at Emory University School of Medicine and a co-author, said the findings underscore the complexity of the issue. "Although race and sex differences in the use of drug therapy were attributable to other patient factors, race and sex differences in use of procedures persisted even after accounting for these factors, and the question is why. What is it about procedures that results in race and sex differences in treatment that we don't see with drugs? And while we have some hypotheses, the answer is really, we don't know," she said, noting that this is an area for further research.
Other authors included Yale investigators Harlan M. Krumholz, MD, and Saif S. Rathore, MPH; Paul D. Frederick, MPH, MBA, of the Ovation Research Group; Jerome L. Abramson, PhD, and Susmita Mallik, MD, of Emory University; Ajay Manhapra, MD, of Hackley Hospital in Spring Lake, Michigan; and Hal V. Barron, MD of Genentech.
Journal
New England Journal of Medicine