1. Overview of study populations.
| Intervention(s) and comparator(s) | Screened/eligible [N] | Randomised [N] | ITT [N] | Finishing study [N] | Randomised finishing study [%] | Follow‐up | |
| (1) Angrisani 2007 | Laparoscopic Roux‐en‐Y gastric bypass | 24 | N/A | 21 | 87.5 | 10 years | |
| Laparoscopic adjustable gastric banding | 27 | N/A | 22a | 81.5 | |||
| total: | ‐ | 51 | N/A | 43 | 84.3 | ||
| (2) Aasheim 2009 | Laparoscopic Roux‐en‐Y gastric bypass | 31 | N/A | 31 | 100 | 2 years | |
| Laparoscopic biliopancreatic diversion with duodenal switch | 29 | N/A | 27 | 93.1 | |||
| total: | 64 | 60 | N/A | 58 | 96.7 | ||
| (3) Demerdash 2013 | Laparoscopic Roux‐en‐Y gastric bypass | ‐ | N/A | 16 | ‐ | 1 year | |
| Laparoscopic adjustable gastric band | ‐ | N/A | 18 | ‐ | |||
| total: | ‐ | 40 | 34 | 85 | |||
| (4) Dixon 2008 | Laparoscopic gastric banding in addition to the conventional therapy | 30 | 30 | 29 | 96.7 | 2 years | |
| Conventional therapy | 30 | 30 | 26 | 86.7 | |||
| total: | 158 | 60 | 60 | 55 | 91.7 | ||
| (5) Dixon 2012 | Laparoscopic adjustable gastric banding and lifestyle programme | 30 | 30 | 28 | 93.3 | 2 years | |
| 2‐year conventional weight loss programme and lifestyle programme | 30 | 30 | 26 | 86.7 | |||
| total: | 130 | 60 | 60 | 54 | 90 | ||
| (6) Hedberg 2012 | Open biliopancreatic diversion with duodenal switch | 24 | N/A | 21 | 87.5 | 4 years | |
| Open Roux‐en‐Y gastric bypass | 23 | N/A | 20 | 87 | |||
| total: | 99 | 47 | N/A | 41 | 87.2 | ||
| (7) Himpens 2006 | Laparoscopic gastric banding | 40 | ‐ | ‐ | ‐ | 3 years | |
| Laparascopic isolated sleeve gastrectomy | 40 | ‐ | ‐ | ‐ | |||
| total: | ‐ | 80 | N/A | ‐ | ‐ | ||
| (8) Ikramuddin 2013 | Laparoscopic Roux‐en‐Y gastric bypass + lifestyle programme with medical management | 60 | 60 | 57b | 95 | 1 year | |
| Lifestyle programme with medical management | 60 | 60 | 57b | 95 | |||
| total: | 2648 | 120 | 120 | 114 | 95 | ||
| (9) Karamanakos 2008 | Laparoscopic Roux‐en‐Y gastric bypass | 30 | N/A | 29 | 96.7 | 3 years | |
| Laparoscopic sleeve gastrectomy | 30 | N/A | 28 | 93.3 | |||
| total: | 60 | 60 | N/A | 57 | 95 | ||
| (10) Keidar 2013 | Laporoscopic Roux‐en‐Y gastric bypass | 22 | N/A | 19 | 86.4 | 1 year | |
| Laparoscopic sleeve gastrectomy | 19 | N/A | 18 | 94.7 | |||
| total: | ‐ | 41 | N/A | 37 | 90.2 | ||
| (11) Lee 2011 | Simplified laparoscopic mini‐gastric bypass with duodenum exclusion | 30 | 30 | 30 | 100 | 1 year | |
| Laparoscopic sleeve gastrectomy without duodenum exclusion | 30 | 30 | 30 | 100 | |||
| total: | 209 | 60 | 60 | 60 | 100 | ||
| (12) Liang 2013 | Usual care | 36 | N/A | 36 | 100 | 1 year | |
| Usual care + exenatide | 36 | N/A | 34 | 94.4 | |||
| Laparoscopic Roux‐en‐Y gastric bypass | 36 | N/A | 31 | 86.1 | |||
| total: | ‐ | 108 | N/A | 101 | 93.5 | ||
| (13) Mingrone 2012 | Gastric bypass | 20 | N/A | 19 | 95 | 2 years | |
| Medical therapy | 20 | N/A | 18 | 90 | |||
| total: | 72 | 40 | N/A | 37 | 92.5 | ||
| (14) Nguyen 2009 | Laparoscopic Roux‐en‐Y gastric bypass | 125 | N/A | 71 | 56.8 | 4 years | |
| Laparoscopic adjustable gastric banding | 125 | N/A | 30 | 24 | |||
| total: | ‐ | 250 | N/A | 101 | 40.4 | ||
| (15) Nogués 2010 | Laparascopic Roux‐en‐Y gastric bypass | 7 | 7 | 7 | 100 | 1 year | |
| Laparoscopic sleeve gastrectomy | 8 | 8 | 8 | 100 | |||
| total: | 30 | 15 | 15 | 15 | 100 | ||
| (16) O'Brien 2006 | Laparoscopic adjustable gastric band | 40 | N/A | 39 | 97.5 | 2 years | |
| Intensive non‐surgical programme | 40 | N/A | 40 | 100 | |||
| total: | 158 | 80 | N/A | 79 | 98.8 | ||
| (17) Paluszkiewicz 2012 | Open Roux‐en‐Y gastric bypass | 36 | ‐ | 35 | 97.2 | 1 year | |
| Laparoscopic sleeve gastrectomy | 36 | ‐ | 34 | 94.4 | |||
| total: | 86 | 72 | ‐ | 69 | 95.8 | ||
| (18) Peterli 2012 | Laparoscopic Roux‐en‐Y gastric bypass | 110 | N/A | N/A | N/A | 3 years | |
| Laparoscopic sleeve gastrectomy | 107 | N/A | N/A | N/A | |||
| total: | ‐ | 217c | N/A | N/Ad | N/A | ||
| (19) Praveen Raj 2012 | Laparoscopic duodenojejunal bypass with sleeve gastrectomy | 28 | ‐ | ‐ | ‐ | 1 year | |
| Laparoscopic Roux‐en‐Y gastric bypass | 29 | ‐ | ‐ | ‐ | |||
| total: | ‐ | 57 | ‐ | ‐ | ‐ | ||
| (20) Schauer 2012 | Intensive medical therapy alone | 50 | N/A | 41 | 82 | 1 year | |
| Intensive medical therapy plus laparoscopic Roux‐en‐Y gastric bypass | 50 | N/A | 50 | 100 | |||
| Intensive medical therapy plus laparoscopic sleeve gastrectomy | 50 | N/A | 49 | 98 | |||
| total: | 218 | 150 | N/A | 140 | 93.3 | ||
| (21) Sharma 2013 | Laparoscopic gastric imbrication | ‐ | 15 | N/A | 12 | 80 | 3 years |
| Laparoscopic sleeve gastrectomy | ‐ | 15 | N/A | 14 | 93.3 | ||
| total: | ‐ | 30 | N/A | 26 | 86.7 | ||
| (22) Vix 2013 | Laparoscopic Roux‐en‐Y gastric bypass | 45 | N/A | 44 | 97.8 | 1 year | |
| Laparoscopic sleeve gastrectomy | 55 | N/A | 48 | 87.3 | |||
| total: | 410 | 100 | N/A | 92e | 92 | ||
| Grand total | All surgical interventions | 1496 | |||||
| All non‐surgical comparators | 302 | ||||||
| All surgical interventions and non‐surgical comparators | 1798 | ||||||
"‐" denotes not reported
aNine patients with band removal excluded from analysis at 10 years (therefore 13 patients included at 10 years) bData for missing patients were included in the ITT analysis using multiple imputation (statistical method specified) cAuthors state that 225 patients were randomised, but 8 patients were excluded after randomisation dTrial is ongoing, presented results were based on an interim analysis eVix 2013 reported 8 were lost to follow‐up (1 laparoscopic Roux‐en‐Y gastric bypass, 7 laparoscopic sleeve gastrectomy) but also reported one per group was lost to follow‐up. Data extracted here are from first statement.
ITT: intention‐to‐treat; N/A: not applicable