MONDAY, Dec. 22, 2014 (HealthDay News) -- Obese heart-failure patients appear to live longer than people of normal weight who develop the disabling condition, a new study suggests.
Researchers tracked nearly 1,500 heart failure patients, most of whom were overweight or obese before their diagnosis. They found that 38 percent of obese and 45 percent of overweight patients died over 10 years, compared with 51 percent of normal-weight patients.
The difference held even if they also had other health issues such as diabetes or high blood pressure.
"At this time the reasons for this beneficial association are not clear," said lead researcher Dr. Anita Deswal, a professor of medicine at Baylor College of Medicine in Houston.
It's possible that "fat itself may be protective," said Dr. Gregg Fonarow, a professor of cardiology at the University of California, Los Angeles, who wasn't involved in the study.
However, Fonarow cautioned that this study doesn't give you a license to gain weight in hopes of living longer should you develop heart failure. The association seen in the study does not prove a cause-and-effect relationship.
"These findings should not be taken as an excuse for individuals without heart failure to gain weight, as this would only increase the risk of developing heart failure, other heart disease, and diabetes in the first place," said Fonarow, a spokesman for the American Heart Association.
It's known that obesity increases the risk for heart failure, which means the heart can't pump blood as it should. However, several investigators have found that in patients with heart failure, overweight and obesity are associated with better survival, compared with normal weight. This is often referred to as the "obesity paradox," Deswal said.
It is possible that obese and overweight heart failure patients are better able to use hormones and enzymes to support heart function than the normal-weight patients, she noted. Thus, obesity may provide a survival advantage when spontaneous weight loss occurs as heart failure gets worse, she said.
"However, it is also possible that obese individuals may show symptoms of heart failure, such as shortness of breath and swelling, at an earlier stage of heart failure and be diagnosed earlier," she said.
This may give rise to the apparent finding that they live longer, Deswal said.
She said this is the first study to show that patients who were obese before developing heart failure appear to survive longer than normal-weight patients.
Fonarow said these findings provide evidence that the obesity paradox in heart failure is not simply the result of the usual weight loss after the onset of heart failure.
Deswal added that whether losing weight could have delayed heart failure isn't known.
Also, "the current study cannot answer whether obese patients with heart failure could have an improvement in symptoms and outcomes if they intentionally lose weight," she said.
For the study, Deswal's team collected data on 1,487 people with heart failure who took part in the Atherosclerosis Risk in Communities study, an ongoing study conducted in four U.S. communities.
Among these patients, 35 percent were overweight and 47 percent were obese about four years before their diagnosis. Over a decade of follow-up, 43 percent of the patients died. Survival odds were better for those who started out overweight or obese, the researchers found.
The report appears in the Dec. 30 issue of the Journal of the American College of Cardiology.
For more on heart failure, visit the American Heart Association.
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