Severely obese individuals who opt to have gastric bypass surgery not only reduce their waistlines, they reduce their long-term total mortality as well, Utah researchers reported.
Rates of death from diabetes, coronary artery disease, and cancer were all significantly lower in 7,925 patients who underwent gastric bypass between 1984 and 2002, Ted D. Adams, Ph.D., and his associates wrote.
Compared with a group of similarly obese control subjects who did not have the surgery, the gastric bypass group had a statistically significant, 40% decrease in adjusted long-term mortality from any cause during the mean follow-up of 7.1 years (37.6 vs. 57.1 deaths/10,000 person-years).
Deaths from coronary artery disease decreased by 56% (2.6 vs. 5.9/10,000 person-years), deaths from diabetes were reduced by 92% (0.4 vs. 3.4/10,000 person-years), and deaths from cancer dropped by 60% (5.5 vs. 13.3/10,000 person-years).
However, the rate of death from all nondisease causes, such as accidents and suicides, was 58% higher in the surgery group than in the control group, wrote Dr. Adams, professor in the division of cardiovascular genetics at the University of Utah, Salt Lake City, and his associates (N. Engl. J. Med. 2007;357:753–61).
The findings should help clinicians and their patients weigh the risks and benefits of gastric bypass, Dr. Adams commented in an interview.
The retrospective cohort study compared long-term mortality among severely obese men and women who had chosen gastric bypass surgery with that of an equal number (7,925) of severely obese persons who had applied for driver's licenses in Utah. The two groups were matched for age, gender, and body mass index. The rates of death from any cause and from specific causes were determined with the use of the National Death Index.
The reduced mortality from disease likely is related to the improvements in health that follow significant weight loss, such as reduced blood pressure, lower diabetes and coronary artery disease risk, and reduced sleep apnea, said Dr. Adams, who is also a program director at the Health and Fitness Institute at Latter Day Saints Hospital, Salt Lake City.
When asked the reason for the higher rate of nondisease deaths in the bariatric surgery group, he said it was difficult to know. “There have been suggestions that some individuals who have undergone gastric bypass surgery may go on to increase their intake of alcohol. There is the thought that perhaps the addictive behaviors related to some obesity may be continued with substance abuse.”
He also suggested that the significant weight loss may lead patients to become more physically active, and thus at greater exposure to accidents.
The finding that cancer deaths were lower after bypass surgery was a surprise, especially because this occurred within the relatively short time frame of 7.1 years, Dr. Adams said. “This reduction persisted even after we excluded prevalent cancers and deaths from cancer occurring within 5 years after baseline. It really interested us that in such a short period of time we would see such a dramatic reduction in cancer.”
The finding has prompted the investigators to do additional research on cancer types and staging after gastric bypass. The investigators also are studying morbidity after gastric bypass; results of that trial, which has been ongoing for the last 5 years, are expected soon, Dr. Adams said.
He emphasized that individuals should take the time to consider the pros and cons of gastric bypass surgery, especially in light of his study's results. “This surgery, which has been shown to be effective for long-term weight loss, also provides a reduction in long-term mortality. But even in light of this research, we would never want individuals to lose track of the very important step they should take to weigh the benefits of the surgery with the risks.”
'It really interested us that in such a short period of time we would see such a dramatic reduction in cancer.' DR. ADAMS
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