Mortality after bariatric surgery: findings from a 7-year multicenter cohort study

Abstract

Background: Patients having bariatric surgery have lower mortality compared with those with similar body mass index who do not undergo surgery. It is unclear whether mortality post-bariatric surgery is similar to the general population. The benefit of bariatric surgery would be highlighted should people previously at high risk for premature death have comparable, or better, mortality as the general population.

Objective: To compare mortality after bariatric surgery to the general U.S. population of the same age, sex, and race.

Setting: The Longitudinal Assessment of Bariatric Surgery-2 (LABS-2) prospective cohort of 2458 adults who underwent bariatric surgery at 10 U.S. hospitals between 2006 and 2009.

Methods: Deaths were identified via LABS-2 follow-up and the National Death Index. Standardized mortality ratios (SMR) of post-bariatric surgery mortality observed in LABS-2 versus age-, sex-, race-, and year-adjusted expected mortality in the general U.S. population were calculated and compared with 1, which results when the number of observed and expected deaths are equal.

Results: LABS-2 median follow-up was 6.6 (interquartile range: 5.9-7.0) years postsurgery. Seventy-six deaths were observed over 15,616 person-years (PY) of observation (4.9 deaths/1000 PY). The rate expected in the general U.S. population with the same age, sex, race, and year distribution was 4.8 deaths per 1000 PY (SMR = 1.02, 95% confidence interval [CI]: .80-1.27). There were no significant differences between observed and expected mortality by surgical procedure. Compared with expected mortality in the general U.S. population, people 35-44 years old at time of surgery had significantly more deaths (SMR = 2.06, 95% CI: 1.22-3.25), while people at least 55 years of age had significantly fewer (SMR = .63, 95% CI: .42-.92). Significantly more deaths than expected occurred in the perioperative period and 5-7 years after surgery.

Conclusions: Mortality within 7 years of bariatric surgery is comparable to the general U.S. population, which is likely to have better survival than people with severe obesity. However, more deaths than expected were identified 5-7 years after surgery.

Keywords: Bariatric surgery; Laparoscopic adjustable gastric banding; Long-term mortality; Mortality; Roux-en-Y gastric bypass.