Obese adults who undergo weight-loss surgery are more likely to survive the next decade than those who don’t. A study in the January 6 JAMA finds that, compared with obese people who had no surgery, patients who elected bariatric surgery had mortality rates roughly half as high 5 and 10 years after the operation.
Earlier research had shown the surgery can induce weight loss, reverse type 2 diabetes in many people and protect against heart problems (SN: 9/10/2011, p. 26
). Some studies also showed lower mortality rates, but those data largely came from women and young to middle-aged adults.
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Nearly three-fourths of the patients in the new analysis were men who were, on average, in their early 50s when they got the surgery. “This gives us evidence that even for older patients there is a survival benefit,” and that it extends to men, says Guilherme Campos, a bariatric surgeon at the University of Wisconsin–Madison, who wasn’t involved in the study. The findings are important because “physicians like to have a thorough understanding of what they are prescribing to patients,” he says.
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The researchers used information from a database of veterans to identify 2,500 men and women who underwent bariatric surgery between 2000 and 2011. The scientists then identified a control group of data from 7,115 other vets. For each surgical patient, the researchers identified roughly three people who matched them in age, weight and medical history. People in both groups were very obese at the outset with an average body mass index in the mid-40s. A person with a BMI of 30 or greater is considered obese.
Follow-up ranged from a few years up to 14. At the five-year point after surgery, 10.4 percent of the people who did not have surgery had died, while fewer — 6.4 percent — of those who got surgery had died. At the 10-year mark, the death rate was 23.9 percent among controls and 13.8 percent in the surgery group.
“It’s not a slam dunk that every obese patient should have [bariatric surgery], but every patient should be having a conversation with their doctor,” says study coauthor David Arterburn, an internist at the Group Health Research Institute in Seattle.
Campos agrees but cautions that people in bariatric surgery studies such as this one aren’t randomly assigned to surgery. Randomization is the gold standard for determining the value of medical treatments because it removes self-selection that might impact the findings, Campos warns. People opting for major surgery could be more driven to improve their health, he says. “These patients need to be willing to change their eating habits and lifestyles.”
Nevertheless, Campos says, the new data are the best available. “I think a randomized controlled trial is not feasible at this point,” he says. “It’s likely not ethical” because the medical benefits of the surgery are becoming clear and widely accepted.
Successful bariatric surgery leads to weight loss by speeding the sensation of feeling full. An individual who gets full faster eats smaller portions and typically consumes fewer calories overall.
The new study also sheds light on trends within bariatric surgery. While three forms of the surgery were included in the analysis, only 10 percent of the surgery group underwent adjustable gastric banding, in which a belt-like device is inserted internally around the stomach. Banding hasn’t shown the consistent weight-loss and anti-diabetes effects of more invasive surgeries, so it’s falling out of favor, says Arterburn.
The other two operations, called gastric bypass and sleeve gastrectomy, reroute food passage through the gut, curbing appetite and reducing the amount of nutrients absorbed. The procedures come with greater up-front surgical risks but often lead to remarkable results.
Despite successes, questions remain, Arterburn says. “We still don’t know at 10 to 20 years what proportion of patients kept most of the weight off.” And it will take years of monitoring patients to know if there are long-term negative consequences from the surgeries that don’t show up earlier. A 2007 study hinted at increased suicide among surgical patients. Some research suggests alcohol use increases after surgery, especially in men.
Campos notes that research also finds an increase in accidental death post-surgery. “Maybe these people are out there doing stuff they didn’t do before,” he says. “Or patients may exchange one addiction for another.”
Editor’s note: This article was updated on January 14, 2015, to correct the number of patients whose data were used for the control group.