June 13, 2011 -- Extremely obese adults who are middle-age or older may not be lengthening their lives by having weight loss surgery, a new study reveals.
These findings differ from previous research, which has shown a modest improvement in survival rates. Other studies done on younger, female, or healthier populations have suggested an increased life span following these procedures.
But this current study looked at an older, predominantly male, and sicker group of adults, and the results did not show a decrease in mortality rates in patients after gastric bypass surgery during a nearly seven-year follow-up period.
"We looked at Roux-en-Y gastric bypass because that was the predominant procedure done when the research was conducted," says study researcher Matthew Maciejewski, PhD, an investigator at the center for Health Services Research in Primary Care at the Durham Veterans Affairs Medical Center in Durham, N.C.
The research appears in the June 15 issue of the Journal of the American Medical Association.
Researchers analyzed data from 850 veterans who had weight loss surgery between January 2000 and December 2006 at one of 12 VA medical centers and a similar number of severely obese high-risk veterans who did not have the operation but received their health care from the same facilities. Among the surgical patients, 74% were male and 26% were female. Their average age was 49 and the average body mass index (BMI) was 47, which is considered severely obese.
When researchers compared mortality rates in the surgical group to a matched nonsurgical control group -- who had a similar age, BMI, race, gender mix, marital status, and number of participants who were super-obese (BMI of 50 or above) -- they did not find a lower mortality rate.
Why didn't gastric bypass extend life? Maciejewski says one possibility is that there is no survival benefit from weight loss surgery in this higher-risk, predominantly male group of patients after nearly seven years. A second explanation is that there could be a longer-term benefit that researchers didn't have enough time to observe.
A study from Sweden with a longer follow-up period found a survival benefit in patients, but it was not seen until an average of 13 years after weight loss surgery.
"In the Swedish research, some of the decreases in mortality found a decade or more later were caused by a reduction in deaths from cancer and heart disease," says Janey Pratt, MD, a bariatric surgeon and director of the Massachusetts General Hospital Weight Loss Center in Boston, who was not involved in either of the two studies. "Perhaps in this latest research, the damage had already been done in older patients, and they're less likely to reap the benefits of surgery in terms of survival.”