Bariatric surgery linked to longer lifespan
Last Updated: 2007-08-22 17:00:39 -0400 (Reuters Health)
By Anthony J. Brown, MD
NEW YORK (Reuters Health) - As a treatment for severe obesity, bariatric surgery significantly lengthens patients' life expectancy in the long term, according to the findings from two studies appearing in The New England Journal of Medicine.
In one study, Dr. Lars Sjostrom, from Sahlgrenska University Hospital in Gothenburg, Sweden, and colleagues assessed mortality in 4,047 patients enrolled in the Swedish Obese Subjects study. Of the subjects, 2,010 underwent bariatric surgery, and another 2,037, who served as a comparison group, did not. The average follow-up period was 10.9 years.
Bariatric surgery refers to an operation performed to limit the amount of food that the stomach can hold. There are two main approaches: gastric bypass, in which the digestive tract is surgically altered to literally bypass most of the stomach; and gastric banding, in which a large portion of the stomach is tied off, leaving only a small pouch. Both methods result in a dramatic reduction in the size of the stomach.
Minimal weight change occurred in the comparison group. By contrast, in the surgery group, weight loss ranged from 20 percent with gastric banding to 32 percent with gastric bypass in the first 2 years after surgery. At 10-year follow-up, weight loss in the surgery group ranged from 14 percent with gastric banding to 25 percent with gastric bypass.
Overall, 129 deaths occurred in the control group compared with 101 in the surgery group. After adjusting for the data for the effects of gender, age, and various risk factors, bariatric surgery reduced the risk of death by 29 percent. Cancer and heart attacks were the most common causes of death in both groups.
In the second study, Dr. Ted D. Adams, from the University of Utah School of Medicine in Salt Lake City, and colleagues compared mortality in 7,925 severely obese patients who underwent gastric bypass surgery and 7,925 matched comparison subjects. The National Death Index was used to assess the rate of deaths from all causes and from specific causes. The average follow-up period was 7.1 years.
Gastric bypass surgery was associated with a 40-percent reduction in the risk of death from any cause, the report indicates. In terms of specific causes, surgery was associated with a 56 percent, 92 percent, and 60 percent reduction in the risk of death from coronary artery disease, diabetes, and cancer, respectively.
By contrast, gastric bypass surgery was associated with 58-percent higher mortality from non-disease causes, such as suicide and accidents.
"We were not surprised at the significant reduction in total mortality of 40 percent. We were surprised that cancers were significantly reduced and that deaths from causes other than disease were increased," Adams told Reuters Health.
"We still need to study in more detail cancer-specific deaths and how weight loss reduces cancer mortality. This analysis is ongoing. We need to understand why patients, despite a generally improved health-related quality of life, have more suicides, accidents and poisonings," he added.
"Finally, we need to further study risk factors for early death in severely obese subjects and see which risk factor improvements are directly responsible for the reduction in mortality."
SOURCE: The New England Journal of Medicine, August 23, 2007.
