MONDAY, Nov. 8, 2004 (HealthDayNews) -- A specific combination of drugs produced such encouraging results in blacks with heart disease that the trial was halted early so all the participants could take advantage of the therapy.
The two drugs reduced death rates by 43 percent.
"The trial was begun in June of 2001 and terminated prematurely in July of 2004 upon the recommendation of the Independent Data Safety Monitoring Committee because of a significant benefit," said lead investigator Dr. Anne Taylor, a professor of medicine at the University of Minnesota Medical School.
The finding was presented Monday at the American Heart Association's scientific sessions in New Orleans, and will appear in the Nov. 11 issue of the New England Journal of Medicine. And it touched off a discussion about the relationship between race and disease among researchers attending the conference.
"The likelihood is that this drug combination would perhaps benefit all racial groups, but what we can say assuredly is that African-Americans will benefit from this therapy," said Dr. Augustus Grant, past president of the American Heart Association (AHA) and of the Association of Black Cardiologists.
Black Americans aged 45 to 64 have two-and-a-half times the mortality rate from heart failure as other races, Taylor noted. Significant differences in responses to treatment have also been seen between blacks and other groups.
It's not clear what biological mechanisms are responsible for these differences. But speculation has centered on the fact that blacks have less bioavailability of nitric oxide, a molecule that is extremely important in the regulation of various aspects of the cardiovascular system.
Previous research had shown that blacks have a strong response to the two drugs that were the focus of the study -- isosorbide dinitrate and hydralazine. This led to the hypothesis that combining the drugs might improve results for blacks with heart disease.
The study enrolled 1,050 blacks with advanced heart failure. They were randomly selected to receive either a fixed dose of the two drugs added to standard therapy (which included beta blockers and diuretics) or a placebo plus standard therapy. The study was funded by NitroMed Inc. of Lexington, Mass., which makes the drugs.
The death rate in the treatment group was 6.2 percent vs. 10.2 percent in the placebo group, representing a 43 percent reduction. The researchers also saw a 33 percent relative reduction in the rate of first hospitalizations (16.4 percent vs. 22.4 percent) and an improvement in the quality of life among the drug recipients.
"The data also strongly suggest that nitric oxide enhancement is a new and potentially highly effective treatment for heart failure, especially in African-Americans," Taylor said.
Researchers warned against placing too much emphasis on the category of race.
"Race is a very, very crude marker," said Dr. Raymond Gibbons, chairman of the AHA's Committee on Scientific Sessions Program.
"Ninety-five percent of the variability in genes is within ethnic groups and only 5 percent is across groups," added Salim Yusuf, of the Population Health Research Institute at McMaster University in Hamilton, Ontario, and author of another study being presented at the AHA meeting.
Besides genetics, heart disease is influenced by lifestyle, access to care and even the interaction between the physician and the patient, Taylor said.
Added Yusuf: "I would extrapolate these results to all people in the world. I would still use it if they look Indian or Chinese or white."
The Association of Black Cardiologists has more about blacks and heart disease.