Diabetes Dangerous in Women With Heart Disease

Combination triples risk of heart failure, study finds

WEDNESDAY, Sept. 8, 2004 (HealthDayNews) -- Postmenopausal women with heart disease who also have diabetes have triple the risk of heart failure that nondiabetics do, says a new study.

Researchers at the University of California, San Francisco (UCSF), evaluated data from participants in a heart-hormone replacement study to determine the risk factors for developing heart failure, and found diabetes to be the strongest indicator. In heart failure, also called congestive heart failure, the heart can't pump enough blood to the body's other organs.

The study, appearing in the Sept. 7 issue of Circulation, is not the first to report the diabetes-heart failure link. But study author Dr. Kirsten Bibbins-Domingo said it is one of few to focus on women.

"The diabetes and heart disease link is well-known,'' said Bibbins-Domingo, an instructor in medicine, epidemiology and biostatistics at the UCSF. However, she added that less is known about what leads to heart failure.

"With men, heart failure appears to happen after a heart attack," Bibbins-Domingo said. "But with women, there is some indication that other factors may play a more important role."

To find out, Bibbins-Domingo said, "we took over 2,300 women and looked to see who would develop heart failure. We did our analysis in several different ways. And what we found consistently was that diabetes was by far the factor most strongly predictive of who would get heart failure."

While the team knew that diabetes and heart disease often coexist, Bibbins-Domingo said, what was striking was how strongly the diabetes predicted who would get heart failure.

Overall, the women with diabetes had a threefold higher risk of getting heart failure than did the women without diabetes, Bibbins-Domingo said. And those with uncontrolled diabetes were at even higher risk of a failing heart.

In the study, women with diabetes who had high fasting blood glucose levels, above 300 milligrams per deciliter, had a threefold increased risk of developing heart failure compared with those with diabetes whose fasting blood sugar levels were controlled, from 80 to 150 milligrams per deciliter.

That probably means those with uncontrolled diabetes have a ninefold increased risk of getting heart failure compared with women without diabetes, Bibbins-Domingo said, extrapolating from the data.

Diabetes was the strongest of nine factors the team looked at. Others included atrial fibrillation (an abnormally rapid beat in the heart's upper chamber), who were nearly 2.9 times as likely to get heart failure, and having two or more previous heart attacks, insufficient kidney function, high blood pressure, obesity and current smoking.

Some previous research also suggests diabetes may promote the development of heart failure independent of the heart disease, perhaps by affecting the heart muscle itself, the authors noted.

Women who had multiple problems had even higher risk of getting heart failure, the team found. "If they had diabetes plus other problems such as high blood pressure, they had a six to 10 times higher rate of heart failure than nondiabetics," said Bibbins-Domingo.

"Those with diabetes who were also obese -- with a body mass index or BMI greater than 30 -- had rates of 7 percent per year of heart failure compared to the general population, which is less than 1 percent," she said.

"This is a helpful study that emphasizes the risk factors for heart failure that are particularly strong in women," said Dr. Ann Bolger, an associate professor of medicine at UCSF and vice chairwoman of the American Heart Association's Council on Clinical Cardiology.

It also points to the need to educate people about modifying the risk factors that lead to heart failure by keeping their weight and blood pressure under control, for instance. "We can't avoid all diabetes, but we certainly know that for many people, activity and keeping an optimal weight are powerful tools against diabetes," Bolger said.

Women with heart disease should stop smoking, lose weight if they need to, and make sure their high blood pressure and diabetes, if they have it, are under control, agreed Bibbins-Domingo.

More information

To learn more about heart failure, visit the American Heart Association.

SOURCES: Kirsten Bibbins-Domingo, Ph.D., M.D., instructor, medicine, epidemiology and biostatistics, University of California, San Francisco; Ann Bolger, M.D., associate professor, medicine, University of California, San Francisco, and vice chairwoman, American Heart Association; Sept. 7, 2004, Circulation
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