Biggest risk factors were hypertension, obesity, study found
WEDNESDAY, March 18 (HealthDay News) -- Blacks tend to develop heart failure 20 years earlier than whites, a long-running study shows.
"What we found is that [early] heart failure occurs almost exclusively among blacks, and it is not a rare occurrence," said Dr. Kirsten Bibbins-Domingo, lead author of a report in the March 19 issue of the New England Journal of Medicine. "It affects one in 100 in their 20s and 30s. What this means is that the incidence of heart failure among blacks in their 20s and 30s is that of whites in the 40s and 50s."
The study, which enrolled 5,115 then-healthy young people in four U.S. cities "was initiated by the National Heart, Lung, and Blood Institute to understand how heart disease develops in young people," said Bibbins-Domingo, an assistant professor of medicine at the University of California, San Francisco, and co-director of the Center for Vulnerable Populations at San Francisco General Hospital. The study is just entering its 25th year, she noted.
In the first 20 years, 27 participants developed heart failure, the progressive loss of the ability to pump blood. All but one were black. And while the study did not exclude such factors as genetics and socioeconomic status as potential causes of the difference, it clearly showed a higher incidence of two major risk factors, high blood pressure and obesity, among blacks.
"If you look at blacks and whites at the beginning of the study, they were remarkably similar in risk profiles," Bibbins-Domingo said. The higher incidence of the two major risk factors soon emerged.
"Those risk factors for heart failure were already present in young adults, and they made themselves felt 20 years later," she said.
Some association was found between lower education levels and the risk of future heart failure, Bibbins-Domingo said. But the overriding link was with high blood pressure and obesity.
"From other work, we know that young people are least likely to be aware that they have high blood pressure," she said. "If they do have high blood pressure, they are least likely to be in treatment, and if they are in treatment, they are least likely to have it under control."
Young people don't often go to doctors, and "physicians don't often treat high blood pressure in young people, because they think the consequences are far in the future," Bibbins-Domingo said.
The study "suggests that individual patients and their physicians should be aware of the future dangers of high blood pressure and obesity in young people," she said. "They should try for changes in lifestyle, and should put them on medications when lifestyle interventions don't work."
Those interventions are especially important in young blacks, she said, but the message is often ignored. "The high rate of teenage obesity in the black community suggests that we already are behind the curve," Bibbins-Domingo said.
Dr. Paul Underwood, former president of the Association of Black Cardiologists, was struck by "the interplay between high blood pressure and heart failure" shown by the study.
"Fully 40 percent of those in the study were not on hypertensive therapy at the time they were diagnosed," Underwood said.
The study points up the need to identify and control risk factors including obesity and diabetes, Underwood said. "If we don't get control of the situation, it's going to get much worse," he noted.
It's difficult to tell whether racism underlies the differences seen in the study, said Dr. Eric D. Peterson, a professor of medicine from Duke Clinical Research Institute in Durham, N.C., who wrote a commentary accompanying the report.
"That is hard to prove," Peterson said. "It is a diagnosis of exclusion. Patients don't notice a care differential, but when you look at the results, the care is different."
But doctors are human, and "dealing with people who are more similar to you can influence care," Peterson said. "The doctor-patient relationship can differ to the extent that you feel a commonality with that patient, and the patient feels a commonality with you."
Causes, symptoms and treatment of heart failure are described by the U.S. National Library of Medicine.
SOURCES: Kirsten Bibbins-Domingo, M.D., Ph.D., assistant professor, medicine, University of California, San Francisco; Paul Underwood, M.D., medical director, interventional cardiology, Boston Scientific Corp., Boston; Eric Peterson, M.D., M.P.H., associate professor, medicine, Duke Clinical Research Institute, Durham, N.C.; March 19, 2009, New England Journal of Medicine
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