“…In total, 70 trials with 3402 participants (mean age 54.6 years), were included in the data synthesis ( Table S1 ) 15–73 . These included six trials 18 , 38 , 41 in general surgery, three 34 , 54 , 59 in bariatric surgery, three 15 , 17 in breast cancer surgery, eleven 16 , 23 , 31 , 32 , 47 , 48 , 50 , 65 , 70 , 73 in cardiothoracic surgery, forty-one 19–21 , 24 , 26–30 , 33 , 35–37 , 39 , 40 , 43 , 45 , 49 , 51–53 , 55 , 57 , 58 , 60–64 , 66–69 , 71 , 72 in orthopaedics, three 42 , 44 , 46 in transplant surgery, one 56 in urology, one 25 in gynaecological surgery, and one 22 in trauma surgery. Some papers reported results of trial with multiple treatment arms: for the purpose of the meta-analysis, each treatment arm has been considered as a separate trial.…”