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Meta-analysis finds bariatric surgery has 0.08% mortality rate

Updated: Oct 28, 2021

Bariatric surgery has an overall 0.08% mortality rate with no statistically significant difference between overall, 30-day, 90-day or in-hospital mortality, according to a meta-analysis by UK researchers. The pooled mortality rates by procedure type, revealed that laparoscopic adjustable gastric banding had the lowest rate (0.03 per cent), followed by sleeve gastrectomy (0.05 per cent), one-anastomosis gastric bypass (0.09 per cent), Roux-en-Y gastric bypass (0.09 per cent), and 0.41 per cent for duodenal switch (p<0.001 between operations). The findings were reported in the paper, ‘Perioperative mortality in bariatric surgery: meta-analysis’, published in the British Journal of Surgery.

The authors stated that although bariatric surgery has been demonstrated to be the most effective method for achieving long-term weight loss, only 1% of eligible patients receive bariatric surgery. The reasons for this underutilisation are numerous but patients, healthcare payers, and medical practitioners do have concerns around the safety of bariatric surgery, which may contribute to poor surgical uptake.

Mortality rates from bariatric surgery vary between case studies, registries and randomised controlled trials (RCTs). Therefore, the researchers undertook the systematic review to carry out an updated, contemporaneous meta-analysis of the literature to determine the perioperative mortality rate of bariatric surgery. They also sought to examine the mortality rates from different procedures and report mortality outcomes in the various study types (RCTs, large case series, administrative databases and national registries).


A total of 58 studies (3,650,961 patients) were included in the meta-analysis and 37 RCTs with fewer than 1,000 patients were identified. The authors reported that there were 4,707 deaths – the overall pooled perioperative mortality rate from all studies was 0.08 per cent. The perioperative mortality rate was lowest for laparoscopic adjustable gastric banding (0.03 per cent) and highest for procedures involving biliopancreatic diversion/duodenal switch (BPD-DS) or other malabsorptive procedures (0.41 per cent). Here, they found evidence of statistically significant differences in perioperative mortality rates between procedures (p<0.001).

The outcome showed that there was no statistically significant difference in perioperative mortality rates between different study types: 0.10 per cent for administrative databases, 0.07 per cent for bariatric registry studies and 0.08 per cent for large series. Data from RCT was excluded from the main analysis as they contained small patient numbers; the data revealed there were three deaths from 4,969 patients (0.06 per cent).

“The perioperative mortality rate from bariatric surgery of 0.08 per cent shows that bariatric surgery is safe. This study has confirmed the similarity of results from different types of reporting in the literature,” the authors concluded. “The low mortality risk of RCTs in bariatric surgery is representative of the overall operated population. These data may inform patient decision-making and increase the acceptability of bariatric surgery.”


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