| Studies included | Random sequence generation | Blinding of participants | Blinding of outcome assessment | Incomplete outcome data | Selective reporting | Other bias | Quality grade |
| Afsansh et al. [7] | High | Unclear | Low | Low | Low | Low | B |
| Kristen et al. [17] | Low | Low | Low | Low | Low | Low | A |
| Zeev et al. [8] | Low | Low | Low | Low | Low | Low | A |
| Arai et al. [18] | Low | Low | Low | Low | Low | Low | A |
| Kristi et al. [16] | Low | unclear | Low | Low | Low | Low | B |
| Li et al. [9] | High | Low | Low | Low | Low | Low | B |
| Farid et al. [10] | Low | unclear | Low | Low | Low | Low | B |
| Spafford et al. [21] | Low | unclear | Low | Low | Low | Low | B |
| Kain et al. [11] | Low | unclear | High | Low | Low | Low | B |
| Zeev et al. [20] | High | unclear | unclear | Low | Low | Low | B |
| W. J. Huang [19] | High | unclear | Low | Low | Low | Low | B |
| L. F. Wang et al. [12] | High | unclear | unclear | Low | Low | Low | B |
| J. H. Lou [13] | Low | Low | Low | Low | Low | Low | A |
| G. Y. Zhang [14] | Low | high | unclear | Low | Low | Low | B |
| Q. Xu et al. [15] | High | Low | unclear | Low | Low | Low | B |