Association Between Bariatric Surgery and Long-Term Survival | Journal Scan

Study Questions:

What is the long-term survival in a large multisite cohort of patients who underwent bariatric surgery compared with matched control patients?


In a retrospective cohort study, the investigators identified 2,500 patients (74% men) who underwent bariatric surgery in Veterans Affairs (VA) bariatric centers from 2000-2011 and matched them to 7,462 control patients using sequential stratification and an algorithm that included age, sex, geographic region, body mass index, diabetes, and Diagnostic Cost Group. Survival was compared across patients who underwent bariatric surgery and matched controls using Kaplan-Meier estimators and stratified adjusted Cox regression analyses. Bariatric procedures included 74% gastric bypass, 15% sleeve gastrectomy, 10% adjustable gastric banding, and 1% other. The main outcome measure was all-cause mortality.


Surgical patients (n = 2,500) had a mean age of 52 years and a mean body mass index (BMI) of 47 kg/m2. Matched control patients (n = 7,462) had a mean age of 53 years and a mean BMI of 46. At the end of the 14-year study period, there were a total of 263 deaths in the surgical group (mean follow-up, 6.9 years) and 1,277 deaths in the matched control group (mean follow-up, 6.6 years). Kaplan-Meier estimated mortality rates were 2.4% at 1 year, 6.4% at 5 years, and 13.8% at 10 years for surgical patients; for matched control patients, 1.7% at 1 year, 10.4% at 5 years, and 23.9% at 10 years. Adjusted analysis showed no significant association between bariatric surgery and all-cause mortality in the first year of follow-up (adjusted hazard ratio [HR], 1.28; 95% confidence interval [CI], 0.98-1.68), but significantly lower mortality after 1-5 years (HR, 0.45; 95% CI, 0.36-0.56) and 5-14 years (HR, 0.47; 95% CI, 0.39-0.58). The midterm (>1-5 years) and long-term (>5 years) relationships between surgery and survival were not significantly different across subgroups defined by diabetes diagnosis, sex, and period of surgery.


The authors concluded that those who underwent bariatric surgery compared with matched control patients who did not have surgery had lower all-cause mortality at 5 years and up to 10 years following the procedure.


This study reports that bariatric surgery was associated with a statistically significant reduction in all-cause mortality relative to usual care after 5-14 years of follow-up among obese patients receiving care in the VA health system. The current study contributes to an increasing body of observational evidence that bariatric surgery is associated with better long-term survival than usual care among obese patients. Appropriately designed randomized clinical trials would provide more definitive evidence that bariatric surgery improves survival.

Keywords: Bariatric Surgery, Body Mass Index, Diabetes Mellitus, Gastrectomy, Cause of Death, Gastric Bypass, Obesity, Outcome Assessment (Health Care)

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