One year after the study started, she calculated weight changes; 824 of the patients did not lose weight and, although none of the patients were trying to lose weight, 170 did. About 20 percent had lost more than 4.4 pounds at the one-year mark.
"For each [2.2 pounds] of weight loss, there was a 4 percent increase in heart failure or death," Kutyifa said.
Whether patients were obese or not to start with, they had a higher risk of heart failure or death if they lost weight, Kutyifa said.
The study found a link between weight loss and increased risk of heart failure and death, not cause-and-effect relationship. It didn't go into the reasons for the association, but Kutyifa speculates that those who lost weight without trying "may have some kind of worsening in cardiac function or in their general health status, and that is translated into worse clinical outcomes."
For those with the defibrillator who want to lose weight for health reasons, Kutyifa suggested they do so under the supervision of a doctor. Those who aren't trying to lose weight but do anyway should tell their doctor so they can be monitored for any problems, she said.
"Weight loss may be a warning sign in these patients," she said.
A heart expert discussed the study results.
"Dehydration or overtreatment may have played a role in the weight loss," said Dr. Ravi Dave, a cardiologist at UCLA Medical Center, Santa Monica.
The pounds shed may primarily reflect a loss of water, said Dave, who also is a clinical professor of medicine at the UCLA David Geffen School of Medicine.
"It will be very important not to send the wrong message," Dave said. "We do know that to reduce risk for heart disease, weight loss is important."
The findings need to be looked at in additional studies, he said.
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