Short- and long-term mortality after bariatric surgery: A systematic review and meta-analysis

Aims The objective of this study was to investigate short- (≤ 30 days) and long-term (≥ 2 years) all-cause mortality after bariatric surgery among adult patients with obesity. Materials and methods For short-term mortality, eligible studies comprised randomized controlled trials (RCTs) reporting perioperative mortality. For long-term mortality, eligible studies comprised RCTs and observational studies comparing mortality between obese patients after bariatric surgery and non-operated controls. Random-effects models using a Bayesian or frequentist approach were used to pool effect estimates of short- and long-term mortality, respectively. Results Short-term all-cause mortality based on 38 RCTs involving 4030 patients was 0.18% (95% CI, 0.04%-0.38%) and was higher for open surgeries (0.31%; 95% CI, 0.03%-0.97%) and similar in mixed surgeries (0.17%; 95% CI, 0.03%-0.43%) and restrictive surgeries (0.17%; 95% CI, 0.03%-0.45%). For long-term mortality, 12 observational studies involving 27 258 operated patients and 97 154 non-operated obese controls were included. Of these, 8 studies were eligible for the meta-analysis, which showed a reduction of 41% in all-cause mortality (hazard ratio, 0.59; 95% CI, 0.52-0.67; P < .001). Additionally, operated patients were 0.42 times as likely (95% CI, 0.25-0.72, P < .001) and 0.47 times as likely (95% CI, 0.36-0.63, P < .001) as non–operated obese controls to die from cardiovascular diseases and cancer, respectively. Conclusions Bariatric surgery is associated with low short-term mortality and may be associated with long-term reductions in all-cause, cardiovascular and cancer-related mortality.