MONDAY, June 20, 2005 (HealthDay News) -- At first glance, a new finding that overweight people had a slightly lower risk of death from cardiac bypass surgery than those of normal weight might seem to favor the school of thought that suggests obesity is not a major health risk.
But that analysis doesn't stand up under closer scrutiny, said cardiologists and the physician who led the study.
It's true that "a little extra body fat apparently provides patients a needed source of glucose, which the body burns for energy, to help them recover from surgery," said study author Dr. Ruyun Jin, a postdoctoral fellow at Providence Health Systems Medical Data Research Center in Portland, Ore. His report appears in the June 21 issue of Circulation.
However, overweight people tended to need the bypass surgery at younger age, the study showed. There was a direct relationship between a high body-mass index, an indicator of obesity, and the age at which the surgery was performed. Extremely obese patients, those with a BMI of 40 or higher, needed bypasses at an average age of 60.
"These data do not dissuade the American Heart Association from being concerned about overweight and obesity, and its effect on cardiac health," said Dr. Robert Eckel, president-elect of the association, and an endocrinologist at the University of Colorado Health Sciences Center. "The negative impact of years of excessive body fat on hypertension, diabetes and other heart and stroke health problems remains important."
And, added Dr. Robert Tranbaugh, chief of cardiac surgery at Beth Israel Medical Center in New York City, "If you read the fine print, this study does not endorse supersizing everything."
The overall death rate among the 16,218 people who had bypass surgery at Providence Health System hospitals in Oregon between 1997 and 2003 was 2 percent. The highest death rate, 7.8 percent, was found in a small number of patients -- only 90 of them -- all of whom were underweight. These were older and very small people with an average age of 70, an average height of 5 feet, six inches, and an average weight of 100 pounds.
The mortality rate for people in the normal weight group, with a BMI between 18.5 and 24.9, was 3.1 percent. That was higher than the overall 2 percent death rate in people classified as mildly, moderately or extremely obese.
The finding contradicts indications from previous studies that overweight patients were more likely to die when they had bypass surgery. One possible explanation is that newer surgical techniques and programs can overcome the challenge presented by obese patients, she said.
"Most cardiac surgeons agree that obesity adds a significant degree of complications to bypass surgery," Tranbaugh said.
One significant set of statistics from the study concerned the incidence of obesity. Overall, 37 percent of the people who underwent surgery over the seven years were obese. But that rose from 32 percent at the beginning of the study to 40 percent at the end, an indication of America's growing obesity epidemic, Jin said.
More information
Anyone who needs a reminder of the health risks of obesity can get it from the American Heart Association.
