Aug. 22, 2007 -- Weight loss surgery is known to help severely obese people shed pounds and lower their risk of diabetes, heart disease, and other obesity-related diseases. Now two landmark studies show that the surgery also saves lives.
In separate research, weight loss surgery was associated with a 29% reduction in deaths over an average follow-up of 10 years, compared to those who did not have weight loss surgery.
Both studies are published in the Aug. 23 issue of The New England Journal of Medicine.
Weight loss surgery, says Bray, "is associated with a dramatic reduction in diabetes and other diseases associated with obesity, so it stands to reason that it would positively impact survival. But there has been some question about this, and a few studies have even suggested the opposite."
Weight Loss Surgery vs. No Surgery
In the larger of the two studies, roughly 8,000 gastric bypass patients and 8,000 people who did not have weight loss surgery matched for sex, age, and weight were followed for an average of seven years.
University of Utah School of Medicine researchers reported a 40% overall reduction in deaths among the surgery patients compared to the patients who did not have weight loss surgery.
Researcher Ted D. Adams, PhD, MPH, tells WebMD that the difference in cancer mortality was very surprising.
"We did not anticipate such a large reduction in cancer deaths in such a short time, and we aren't really sure what to make of it," he says, adding that his research team is currently exploring the issue.
Death Rates From Causes Other Than Disease
There was yet another surprise in the findings. While surgery patients had a lower death rate from diabetes, cancer, and other diseases than nonsurgery patients, death rates from causes other than disease, such as accidents and suicide, were greater.
Patients who had weight loss surgery had death rates from nondisease causes that were 58% greater than people who did not have surgery.
The study offered few clues about the reason for this. But several previous studies have suggested a link between weight loss surgery and an increase in drug and alcohol abuse and other risk-taking behaviors.
Adams says the findings highlight the need for better ways to identify psychological "red flags" in patients who are considering weight loss surgery and for assessing mental status after surgery.
Weight Loss Surgery vs. Dieting
The second study involved just over 4,000 severely obese patients, half of whom were treated with weight loss surgery and the other half with either no treatment or nonsurgical weight loss interventions like dieting.
Ten years later, weight loss among the surgery patients averaged 14% to 25%, compared with less than 2% among the nonsurgery patients.
During the follow-up, 129 deaths occurred among nonsurgery patients, compared with 101 deaths among the surgery group. The number of heart attack deaths were lower in the surgery group (13 vs. 25), as were cancer deaths (29 vs. 47).
Researcher Claude Bouchard, PhD, of Louisiana State University's Pennington Biomedical Research Center, tells WebMD that the two studies prove that weight loss surgery is a lifesaving option for severely obese patients.
Consensus Conference Needed
Bray agrees that weight loss surgery may prove to be a more important weapon in the battle against obesity and obesity-related disease than any previous intervention.
But he says the benefits and risks of modern approaches to weight loss surgery must be examined before the indications for the surgery are expanded.
He is calling for a national conference to address the matter. The last such conference was held in 1991.
"A lot has happened since then, he says. "Laparoscopic surgery has all but replaced the open surgery -- and surgical mortality rates have declined as a result. But there are unanswered questions about which patients will benefit most from this surgery."