Table 3 Results of the 22 studies checked for the risk of bias assessment using the SIGN checklist
Study | Item | Total | Overall Assessment | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1.1 | 1.2 | 1.3 | 1.4 | 1.5 | 1.6 | 1.7 | 1.8 | 1.9 | 1.10 | 1.11 | Y | N | CS | NA | ||
Plachel et al. [41] | Y | Y | Y | 100 | Y | Y | Y | CS | Y | Y | Y | 9 | 0 | 1 | 0 | High quality |
Ge et al. [42] | Y | Y | Y | 100 | N | Y | Y | CS | Y | N | Y | 7 | 2 | 1 | 0 | Acceptable |
Hall et al. [43] | Y | Y | Y | 100 | Y | Y | Y | CS | Y | N | N | 7 | 2 | 1 | 0 | Acceptable |
Leal et al. [44] | Y | Y | Y | 100 | Y | Y | Y | CS | Y | N | Y | 8 | 1 | 1 | 0 | Acceptable |
Feng et al. [47] | Y | N | N | N | Y | Y | Y | 0 | CS | Y | - | 5 | 3 | 1 | 0 | Borderline |
Sun et al. [53] | Y | N | N | N | Y | N | Y | 0 | CS | Y | - | 5 | 3 | 1 | 0 | Borderline |
Xiao et al. [57] | Y | N | N | N | Y | CS | Y | 0 | CS | Y | - | 4 | 3 | 2 | 0 | Borderline |
Thankam et al. (2019) | Y | CS | CS | 100 | N | Y | Y | CS | Y | N | Y | 5 | 2 | 3 | 0 | Borderline |
Ge et al. [48] | Y | Y | Y | 100 | N | Y | Y | CS | Y | N | N | 6 | 2 | 2 | 0 | Borderline |
Thankam et al. [40] | Y | CS | CS | 100 | N | Y | Y | CS | Y | N | N | 4 | 3 | 3 | 0 | Borderline |
Han et al. [49] | Y | Y | CS | 100 | N | Y | Y | CS | Y | N | Y | 6 | 2 | 2 | 0 | Borderline |
Brown et al. [46] | Y | CS | Y | 91 | CS | Y | Y | CS | Y | N | N | 5 | 2 | 3 | 0 | Borderline |
Lu et al. [50] | Y | N | N | N | CS | CS | Y | 0 | CS | Y | - | 3 | 3 | 3 | 0 | Borderline |
Thankam et al. [54] | Y | CS | CS | 100 | N | Y | Y | CS | Y | N | Y | 5 | 2 | 3 | 0 | Borderline |
Wang et al. [56] | Y | N | N | N | Y | Y | Y | 0 | CS | Y | - | 5 | 3 | 1 | 0 | Borderline |
Millar et al. [51] | Y | N | N | N | Y | CS | Y | 0 | CS | Y | - | 4 | 3 | 2 | 0 | Borderline |
Peffers et al. [52] | Y | Y | CS | 100 | N | Y | Y | CS | Y | N | N | 5 | 3 | 2 | 0 | Borderline |
Abrahams et al. [45] | Y | Y | CS | 100 | CS | Y | Y | CS | Y | N | N | 5 | 2 | 3 | 0 | Borderline |
Hu et al. [60] | Y | N | N | N | CS | CS | Y | CS | CS | CS | - | 2 | 3 | 5 | 0 | Unacceptable |
Chen et al. [59] | Y | N | N | N | CS | CS | Y | CS | CS | CS | - | 2 | 3 | 5 | 0 | Unacceptable |
Cai et al. [58] | Y | CS | CS | 100 | CS | Y | Y | NA | Y | N | N | 4 | 2 | 3 | 1 | Unacceptable |
Poulsen et al. [61] | Y | N | N | N | CS | CS | Y | CS | CS | CS | - | 2 | 3 | 5 | 0 | Unacceptable |