Sunday, November 12, 2006

Heart Disease Death Rate Higher Among African Americans
By Julie McKeel

Kevin Thomas, MD

The study was supported by a young investigator award from the Association of Black Cardiologists and the Duke Clinical Research Institute. The study results were reported on Sunday, Nov. 12, at the annual scientific sessions of the American Heart Association, in Chicago.

The researchers analyzed the records for patients diagnosed with serious coronary disease, followed for an average of nine years. Among this population, black patients have had a 36% survival rate while whites have had a 46% survival rate.

This disparity, according to the researchers, can be explained, in part, by the findings that blacks tend to have higher rates of other medical conditions, which can complicate or contribute to heart problems. Also, black patients do not receive coronary artery bypass surgery as often. However, other unproven factors almost certainly are involved and the researchers stressed that further research is necessary to identify these factors and measure their impact on the disparity.

"As prevention becomes a key point of emphasis in treating heart disease, it is vitally important to identify risk factors and to act on them," said the DCRI's Kevin Thomas, M.D., the cardiology fellow who reported the results of the study.

"Past studies from which risk factors have been derived provide great information about heart disease in white men, but the studies have included few minorities and women," Thomas told DukeMedNews. "Cardiovascular disease is the leading cause of death for blacks and whites in the United States , and yet there is a paucity of information on the long-term prognosis for blacks."

Thomas, along with DCRI colleagues Emily Honeycutt, Linda Shaw, and Eric Peterson, consulted the Duke Database for Cardiovascular Disease, a repository of data collected on heart patients who come to Duke University Medical Center for diagnosis and treatment. The team analyzed the outcomes of 21,054 patients with serious coronary artery disease, seen between 1986 and 2004. Of those patients, 3,177 were black.

According to Thomas, the black patients tended to be younger and female, with higher rates of hypertension, diabetes, heart failure or previous heart attacks. Even after the team statistically accounted for those patient characteristics, the disparity in death rates persisted. This finding meant that other factors must be contributing to the disparity.

"When we looked at the extent of coronary disease, we found there was little difference between blacks and whites," Thomas told DukeMedNews. "However, when we looked at the incidence of procedures received by patients within 30 days of cardiac catheterization, we found that whites were 12% more likely to receive coronary bypass surgery."

While it is not clear from the patient records why blacks did not receive coronary bypass surgery as often as whites, one possible explanation suggested by the researchers is that some physicians may have been biased against blacks, whether intentionally or not. This bias has been shown in past Duke studies. Thomas also indicated that many blacks have a historical mistrust of the medical system, and so black patients might not have been as willing to undergo an invasive procedure such as the coronary bypass surgery.

"A big part of that mistrust is communication," Thomas told DukeMedNews. "If black patients don't have a complete understanding of the procedure, or if it is not explained well, they may decline the procedure. If a physician or health care provider explains the procedure and what it entails, more black patients might agree to the surgery -- especially if the person doing the explaining were black or trained to be culturally sensitive."

Aside from less use of bypass surgery, other factors probably contributed to the disparities and should be investigated in future studies.

For example, the researchers noted that heart patients typically receive optimal care while they remain in the hospital. Yet when patients return to their home environment, they can't always follow their doctor's advice or maintain a healthy lifestyle. Patients may forget to fill their prescriptions or continue taking the medicine over the long term. Or patients will resume smoking or poor diet habits. These patients may not go back to see their doctor, or they may not have doctors that they see regularly. According to Thomas, these obstacles may disproportionately affect minority populations.

The medical community needs to find ways to attract more blacks into participating in clinical trials in order to learn more about what treatments work best for individual patients.

Because the black community has a history of mistrust of the health care system, clinicians and researchers must learn how to communicate to the specific patient population in a culturally sensitive manner in order to improve outcomes.

According to Thomas, the Association of Black Cardiologists, which is respected and trusted in the black community, is working to improve the levels of minority enrollment in clinical trials of heart disease treatments.

Too, the results from the current Jackson Heart Study, a National Institute of Health supported study focusing on cardiovascular disease among the black residents in and around Jackson , Miss. , should yield important data. This study, Thomas said, may provide advances similar to the ongoing Framingham Heart Study (which began in 1948) with a primary focus on white men.