Weight-loss surgery may not reduce the risk of death in higher risk patients — older, heavier and sicker men — a new study finds.
The findings contradict earlier studies that have documented health and survival benefits for obese people who undergo gastric bypass surgery, also known as Roux-en-Y. But the current study’s authors note that much of the previous research has been done in younger women. MedPage Today reported:
In large men, they noted, the Roux-en-Y procedure is “inherently more difficult” because of anatomical differences from women. The procedure also has a higher perioperative mortality rate in large men.
Men and minority patients with high rates of comorbidity have the highest risk of dying because of their obesity, they noted, and “these patients would potentially benefit the most from bariatric surgery–induced weight loss.” On the other hand, no studies have focused on high-risk patients, they noted.
Thus, for the new study, researchers from the Durham VA Medical Center in North Carolina followed a group of 850 predominantly male veterans who had bariatric surgery at 12 Veterans Affairs medical centers between January 2000 and December 2006. The recipients of surgery had an average age of about 50 and an average body mass index (BMI) of 47.1, which qualified as morbidly obese.
The researchers then compared outcomes for the surgery patients with those of a control group of 41,244 veterans in the VA medical center network. These patients were older (with an average age of 55) and less obese (with an average BMI of 42). When looking at crude mortality rates over a six-year follow-up, the patients who got weight-loss surgery appeared to benefit: about 7% of surgery patients had died versus 15% of those who didn’t get the operation.
But when researchers examined further, carving out a group of 1,694 patients — 847 surgery patients and 847 controls who had been carefully matched for age, weight and medical characteristics — this difference disappeared. People who got bariatric surgery were no more likely to survive than those who didn’t.
“Our results highlight the importance of statistical adjustment and careful selection of surgical and nonsurgical cohorts, particularly during evaluation of bariatric surgery according to administrative data. Previous studies claiming a survival benefit for bariatric surgery had limited clinical information to conduct detailed risk adjustment or matching. The survival differences between the bariatric surgery and control groups were modest in most previous studies, so the beneficial effects of surgery may have been attenuated if adjustment for confounders had been possible,” the authors wrote.