Racial differences in fatal coronary heart disease associated with risk factor burden

Despite treatment advances for coronary heart disease over the past 20 years, black men and women still have twice the risk of fatal coronary heart disease compared with white men and women, according to a study from the University of Alabama at Birmingham appearing in the Nov. 7, 2012 issue of the Journal of the American Medical Association.

Most of this disparity may be due to greater risk factor burden among blacks — including smoking, diabetes and hypertension — suggesting that it could be eliminated with better risk factor control, the researchers say. The study is being released early online to coincide with the American Heart Association Scientific Sessions being held in Los Angeles from Nov. 3-7.

Coronary heart disease rates in the United States have steadily declined since the 1970s for all racial groups. But UAB researchers analyzing death certificate information and other data from four U.S. cities found a steeper decline between 2000 and 2008 in acute coronary heart disease deaths for whites than for blacks, actually widening the longstanding disparity. Data from Kaiser Permanente suggests that hospitalizations for heart attacks between 2002 and 2007 declined greatly, but more so for whites than for blacks.

"During the time period since the last reports on the incidence of heart disease, two things happened - statins came into wider use to manage coronary heart disease, and blood tests to detect heart attacks became more sensitive, enabling physicians to identify much smaller cardiac events," says the study's lead author, Monika M. Safford, M.D., professor in the UAB Division of Preventive Medicine. "However, prior to our study, there were no data on how these two advances have impacted racial and sex differences in coronary heart disease rates."

Safford and colleagues looked at data from the NIH-funded Reasons for Geographic and Racial Differences in Stroke (REGARDS) study to examine total coronary heart disease rates, fatal coronary heart disease rates and nonfatal coronary heart disease rates among blacks and whites, and among men and women. They analyzed whether risk factors for coronary heart disease were associated with the observed differences in risks by race and sex. They also analyzed the effect of very small heart attacks on these differences. All of this was part of their effort to determine if racial differences continue to persist and, if so, to identify possible causes.

Of the 24,443 REGARDS participants included in the UAB study, blacks and whites had a similar average age, but inactivity, smoking, diabetes and reduced kidney function were more prevalent among blacks compared with whites, and systolic blood pressure and body mass index were higher among blacks as well. The average follow-up time for the participants was 4.2 years. Overall, there were 659 heart attacks recorded: 153 events in black men, 254 in white men, 138 in black women, and 114 in white women.

The researchers found that although the measured incidence rate of total coronary heart disease was similar among black men and white men, black men had a higher incidence of fatal coronary heart disease and a lower incidence of nonfatal coronary heart disease. Women had lower incidence rates than men within each racial group. However, black women had higher incidence rates than white women for total coronary heart disease, fatal coronary heart disease and nonfatal coronary heart disease.

Overall, compared with past studies, the UAB researchers found that racial differences persist in fatal coronary heart disease rates and that the rate is associated with risk factor burden, Safford says.

"Excess risk factors among black men and women continue to be a major public health challenge, which may be contributing to their high risk for death from coronary heart disease," Safford says. "It's very hard to prevent future heart disease when people die of their first sign of heart disease. This is frustrating because we have effective interventions available. To potentially reduce these persistent disparities, we need to improve our interventions targeted at this high-risk group, optimizing education and treatment for these well-established coronary heart disease risk factors among blacks."