TABLE 1.
Baseline demographic
| Reference | Site | Study type | Sample size, n | Age, mean ± SD, median (range) | Female: male, n | Type of surgery | Duration of study, months | NOS score |
|---|---|---|---|---|---|---|---|---|
| Gertler 1986 | Australia | Prospective | 20 | 37.2 (24–52) | 0:20 | RYGB, GP, GG, VG | NA | 7 |
| Gertler 1986 | Australia | Prospective | 133 | 34.9 (18–60) | 133:0 | RYGB, GP, GG, VG | NA | 7 |
| Waters 1991 | USA | Prospective | 157 | 36.3 (19–67) | 132:25 | RYGB | 36 | 7 |
| Maddi 2001 | USA | Prospective | 52 | 38.4 (19–56) | 46:6 | 12 | 8 | |
| Dixon 2003 | Australia | Prospective | 487 | 41.2 ± 9.7 | 414:73 | GB | 48 | 7 |
| Mamplekou 2005 | Greece | Prospective | 59 | 37.7 ± 10.7 | 45:14 | VG | 24 | 7 |
| Burgmer 2007 | Germany | Prospective | 149 | 38.8 ± 10.3 | 102:47 | GB, VG | 24 | 8 |
| Karlsson 2007 | Sweden | Prospective | 655 | 47.0 ± 5.7 | RYGB, GB, VG | 120 | 8 | |
| Nickel 2007 | Germany, Austria | Prospective | 21 | 38.0 ± 9.5 | 50:0 | GB | 72 | 7 |
| Scholtz 2007 | UK | Prospective | 29 | 39.0 ± 9.0 | 28:1 | GB | 60 | 8 |
| Schowalter 2008 | Germany | Prospective | 248 | 38.5 ± 10.1 | 200:48 | GB | 67 | 8 |
| Andersen 2010 | Norway | Prospective | 50 | 37.9 ± 7.9 | 28:22 | BPD | 24 | 8 |
| Kruseman 2010 | Switzerland | Prospective | 141 | 40.0 ± 10.0 | 80:0 | RYGB | 96 | 7 |
| Thonney 2010 | Switzerland | Prospective | 43 | 39.2 ± 1.4 | 43:0 | RYGB | 24 | 9 |
| Assimakopoulos 2011 | Greece | Prospective | 59 | 36.0 (18–56) | 59:0 | RYGB, BPD, SG | 12 | 7 |
| Lier 2011 | Norway | Prospective | 127 | 41.3 ± 10.3 | 94:33 | RYGB | 12 | 8 |
| Strain 2011 | USA | Retrospective | 77 | 52.3 ± 12.7 | 54:23 | SG | 24.6 | 6 |
| Zwaan 2011 | Germany | Prospective | 107 | 37.5 ± 9.7 | 75:32 | RYGB, GB | 36 | 8 |
| Jarvholm 2012 | Sweden | Prospective | 37 | 16.6 ± 1.3 | 25:12 | RYGB | 3 | 8 |
| Ortega 2012 | Spain | Prospective | 60 | 44.1 ± 10.9 | 46:14 | RYGB | 12 | 7 |
| Rutledge 2012 | USA | Prospective | 55 | 52.5 ± 7.4 | 17:38 | RYGB, GB | 60 | 8 |
| Sysko 2012 | USA | Prospective | 101 | 15.8 ± 1.1 | 73:28 | GB | 12 | 7 |
| Lier 2013 | Norway | Prospective | 127 | 41.3 ± 10.3 | 125:44 | RYGB | 12 | 8 |
| Burgmer 2014 | Germany | Prospective | 148 | 38.8 ± 10.2 | 101:47 | GB, VG | 96 | 8 |
| Castellini 2014 | Italy | Prospective | 83 | 45.3 ± 10.1 | 75:8 | RYGB, BPD, GB | 12 | 7 |
| Hayden 2014 | Australia | Prospective | 204 | 45.2 ± 11.5 | 168:36 | GB | 24 | 8 |
| Ivezaj 2014 | USA | Prospective | 107 | 42.7 ± 10.5 | 94:13 | GB | 12 | 7 |
| Matini 2014 | Iran | Prospective | 67 | 36.8 ± 8.5 | 55:12 | RYGB | 6 | 9 |
| Mitchell 2014 | USA | Prospective | 2146 | 46.0 (18–76) | 1685:461 | RYGB, GB, SG, BPD | 36 | 7 |
| Strain 2014 | USA | Prospective | 105 | 43.5 ± 10.8 | 76:29 | RYGB, BPD, GB, SG | 24 | 7 |
| Tae 2014 | Brazil | Prospective | 32 | 41.0 ± 11.6 | 32:0 | 10 | 8 | |
| Booth 2015 | UK | Prospective | 3045 | 45.9 ± 10.2 | 2406:639 | RYGB, GB, SG | 96 | 7 |
| Herpertz 2015 | Germany | Prospective | 152 | 39.1 ± 10.3 | 102:50 | GB, VG | 108 | 8 |
| Sockalingam 2015 | USA | Prospective | 164 | 43.5 ± 9.7 | 133:31 | RYGB, SG | 12 | 7 |
| White 2015 | USA | Prospective | 357 | 43.7 ± 10.0 | 307:50 | RYGB | 24 | 7 |
| Jarvholm 2016 | Sweden | Prospective | 82 | 16.8 ± 1.2 | 57:25 | RYGB | 24 | 8 |
| Kalarchian 2016 | USA | Prospective | 165 | 46.0 (21‐68) | 135:30 | RYGB, GB@ | 36 | 8 |
| Mack 2016 | Germany | Prospective | 75 | 45.2 ± 11.6 | 48:27 | SG | 48 | 9 |
| Efferdinger 2017 | Austria | Prospective | 45 | 44.1 ± 13.3 | 34:11 | RYGB, SG | 6 | 7 |
| Osterhues 2017 | Germany | Cross‐sectional | 192 | 40.7 ± 11.4 | 136:56 | RYGB, SG, GB | 19 | 8 |
| Sockalingam 2017 | Canada | Prospective | 156 | 45.2 ± 9.3 | 126:30 | RYGB, SG | 24 | 7 |
| Alabi 2018 | Mexico | Retrospective | 73 | 38.1 ± 9.1 | 56:17 | GB | 12 | 8 |
| Ho 2018 | Canada | Retrospective | 365 | 44.7 ± 10.0 | 292:73 | RYGB, SG | 12 | 8 |
| Hunsaker 2018 | USA | Prospective | 139 | 19.2 ± 1.3 | 162:40 | RYGB, SG, GB | 24 | 8 |
| Monte 2018 | USA | Prospective | 59 | 51.0 ± 13.0 | 51:8 | SG | 6 | 8 |
| Pinto‐Bastos 2018 | Portugal | Prospective | 122 | 42.8 ± 11.4 | 108:14 | RYGB, SG | 6 | 7 |
| Pinto‐Bastos 2018 | Portugal | Prospective | 116 | 47.9 ± 9.2 | 107:9 | 6 | 7 | |
| Ribeiro 2018 | Brazil | Prospective | 281 | 40.7 ± 9.8 | 225:56 | RYGB | 60 | 6 |
| Kalarchian 2019 | USA | Prospective | 104 | 45.0 (21–68) | 84:20 | RYGB, GB | 60 | 8 |
| Kalarchian 2019 | USA | Prospective | 69 | 47.0 (40–54) | 58:11 | 60 | 8 | |
| Hawkins 2020 | Canada | Prospective | 190 | 44.5 ± 10.6 | 156:34 | RYGB, SG | 12 | 7 |
Abbreviations: BPD, biliopancreatic diversion; GB, gastric banding; GG, gastrogastrostomy; GP, gastric partitioning; NA, not available; RYGP, Roux‐en‐Y gastric bypass; SG, sleeve gastrectomy; VG, vertical gastroplasty.