Bariatric surgery may not improve survival in middle-aged obese men, study suggests

Middle-aged obese men who undergo bariatric surgery may not see a survival benefit, according to a new study.

Most studies of survival after bariatric surgery have focused mainly on populations of younger white women, but mortality related to obesity has been found to be highest in men and in minority patients with comorbid conditions. Researchers performed a retrospective cohort study to compare survival in mostly middle-aged severely obese veterans who had undergone bariatric surgery at a Veterans Affairs medical center from January 2000 to December 2006 and in a group of severely obese veterans who had not had bariatric surgery. Patients were followed for a mean of 6.7 years, and the primary outcome measure was all-cause mortality through December 2008. The study results were published online June 12 by the Journal of the American Medical Association.

The surgery group included 850 veterans who had had bariatric surgery (mean age, 49.5 years; mean body mass index [BMI], 47.4 kg/m²) and 41,244 controls who had not (mean age, 54.7 years; mean BMI, 42.0 kg/m²). Approximately 74% of the surgical patients and approximately 92% of the controls were men. The 1-, 2- and 6-year crude mortality rates were 1.5%, 2.2% and 6.8%, respectively, in the surgical group, and 2.2%, 4.6% and 15.2% in the control group. Bariatric surgery was associated with a mortality reduction in unadjusted Cox regression analysis (hazard ratio [HR], 0.64; 95% CI, 0.51 to 0.80) and after covariate adjustment (HR, 0.80; 95% CI, 0.63 to 0.995). However, in an analysis of 1,694 propensity-matched patients, 847 in each group, no significant association was seen between surgery and reduced mortality in unadjusted (HR, 0.83; 95% CI, 0.61 to 1.14) or time-adjusted (HR, 0.94; 95% CI, 0.64 to 1.39) Cox regressions.

The authors acknowledged that their study results may not be generalizable to other groups of patients and that they did not include patients who had had laparoscopic banding procedures. They also noted that Roux-en-Y gastric bypass is more difficult to perform and yields higher mortality rates in larger male patients than in female patients, which may have contributed to the lack of survival benefit. Finally, they wrote that the large CIs in the propensity-matched analysis cannot exclude the possibility that some patients may derive clinical benefit or harm from bariatric surgery, and that their results may be subject to unobserved confounding.

However, they concluded that middle-aged obese men do not see a survival benefit within seven years of bariatric surgery, although longer follow-up may be needed to observe a protective effect. Future studies, they said, should include larger samples and should try to determine which subgroups of patients would benefit most from surgery. “Even though bariatric surgery is not associated with reduced mortality among older male patients, many patients may still choose to undergo bariatric surgery, given the strong evidence for significant reductions in body weight and comorbidities and improved quality of life,” they wrote.