A new study is debunking the "obesity paradox" and found better measures than body mass index to determine heart failure in overweight patients, Science Daily reported March 22.
The "obesity paradox" suggested people who are overweight or obese are more likely to develop heart problems but that those with higher BMIs are less likely to be hospitalized or die than people of normal weight. Various explanations have been put forth, including theories that some extra fat somehow protected against further heart problems and death.
"It has been suggested that living with obesity is a good thing for patients with heart failure and reduced ejection fraction — which is when the main chamber of the heart is unable to squeeze out the normal amounts of blood," John McMurray, MD, professor of medical cardiology at the University of Glasgow (U.K.), said in the report. "We knew this could not be correct and that obesity must be bad rather than good. We reckoned that part of the problem was that BMI was a weak indicator of how much fatty tissue a patient has."
The study, published in the European Heart Journal, analyzed data from 1,832 women and 6,567 men with heart failure and reduced ejection fraction in 47 countries. Researchers collected data on BMI, blood pressure, anthropometric measurements, blood tests, medical histories and treatments. Results indicated that if ratio of waist to height is taken for a patient, rather than BMI, the supposed survival advantage of people with a higher BMI disappears.
"The paradox was far less evident when we looked at waist-to-height ratios, and it disappeared after adjustment for prognostic variables," lead author Jawad Butt, MD, a research fellow from Copenhagen (Denmark) University Hospital-Rigshospitalet, said. "After adjustment, both BMI and waist-to-height ratio showed that more body fat was associated with a greater risk of death or hospitalization for heart failure, but this was more evident for waist-to-height ratio. When looking at waist-to-height ratio, we found the top 20 percent of people with the most fat had a 39 percent increased risk of being hospitalized for heart failure compared to people in the bottom 20 percent who had the least fat."