Evidence synthesis characteristics
| All (n=299) | With protocol (n=88) | Without protocol (n=211) | |
| Review type | |||
| Systematic review with meta-analysis | 189 (63%) | 66 (75%) | 123 (58%) |
| Systematic review | 73 (24%) | 15 (17%) | 58 (27%) |
| Meta-analysis | 12 (4%) | 0 (0%) | 12 (6%) |
| Scoping review | 10 (3%) | 3 (3%) | 7 (3%) |
| Rapid review | 8 (3%) | 1 (1%) | 7 (3%) |
| Network meta-analysis | 2 (1%) | 1 (1%) | 1 (0%) |
| Rapid review with meta-analysis | 2 (1%) | 1 (1%) | 1 (0%) |
| Systematic review with network meta-analysis | 2 (1%) | 0 (0%) | 2 (1%) |
| Overview of systematic reviews | 1 (0%) | 1 (1%) | 0 (0%) |
| Review abstract | |||
| Structured abstract | 159 (53%) | 47 (53%) | 112 (53%) |
| Abstract with no structure | 140 (47%) | 41 (47%) | 99 (47%) |
| Eligibility criteria | |||
| Report eligibility criteria | 259 (87%) | 86 (98%) | 173 (82%) |
| Eligibility criteria are unclear | 40 (13%) | 2 (2%) | 38 (18%) |
| Include randomised controlled trials | |||
| Include RCTs only | 51 (17%) | 19 (22%) | 32 (15%) |
| Include different study designs | 248 (83%) | 69 (78%) | 179 (85%) |
| No of data sources | |||
| Median (IQR) | 5 (3–6) | 6 (4–7) | 4 (3–6) |
| No of included studies | |||
| Median (IQR) | 14 (7–28) | 17 (7–38) | 14 (7–25) |
| Common country | |||
| 1.United States of America | 57 (19%) | 13 (15%) | 44 (21%) |
| 2.China | 40 (14%) | 13 (15%) | 27 (13%) |
| 3.India | 34 (11%) | 12 (13%) | 22 (10%) |
| 4.Iran | 18 (6%) | 3 (3%) | 15 (7%) |
| 4.United Kingdom | 18 (6%) | 3 (3%) | 15 (7%) |
| 5.Saudi Arabia | 13 (4%) | 1 (1%) | 12 (6%) |
| 6.Canada | 12 (4%) | 5 (6%) | 7 (3%) |
| 7.Italy | 12 (4%) | 8 (9%) | 4 (2%) |
| 8.Indonesia | 9 (3%) | 2 (2%) | 7 (3%) |
| 9.Malaysia | 7 (2%) | 0 (0%) | 7 (3%) |
| 10.Egypt | 5 (2%) | 2 (2%) | 3 (1%) |
| 10.France | 5 (2%) | 3 (3%) | 2 (1%) |
| 10.Peru | 5 (2%) | 1 (1%) | 4 (2%) |
| 10.Taiwan | 5 (2%) | 1 (1%) | 4 (2%) |
RCT, randomised controlled trial.