Thirty-six studies (n=2,570 participants) were included in the review: two randomised controlled trials, one non-randomised controlled trial and 33 uncontrolled case series.
The percentage of excess weight loss ranged from 33% to 85% in 24 studies (n=1,662). Overall mean excess weight loss was reported to be 55.4%. More than 70% of participants had an improvement of remission of type 2 diabetes (10 studies, n=754) (other results were presented in tables).
Major postoperative complications ranged from 0% to 23.8% across studies; an overall mortality rate of 0.19% was reported. Postoperative complication rate for studies with more than 100 participants ranged from 0% to 15.3%.