| Inclusion studies | Random sequence generation | Blinding of participants | Blinding of outcome assessment | Incomplete outcome data | Selective reporting | Other bias | Quality grade |
| Liang [11] | unclear | unclear | unclear | low | low | unclear | B |
| Abd-EI-Maeboud [12] | low | low | low | low | low | low | A |
| Luo [13] | unclear | unclear | unclear | low | low | unclear | B |
| Wang [14] | low | unclear | unclear | low | low | low | B |
| Ledari [15] | low | unclear | low | low | low | low | B |
| Ledari [16] | unclear | unclear | unclear | low | low | unclear | B |
| Rashad [17] | unclear | unclear | unclear | low | low | unclear | B |
| Ajuzieogu [18] | low | low | low | low | low | low | A |
| Jian Tao [19] | low | low | low | low | low | low | A |
| Lang [20] | low | unclear | unclear | low | low | low | B |
| Feng [21] | low | unclear | unclear | low | low | low | B |
| Wang [22] | low | unclear | unclear | low | low | low | B |
| Magdy [23] | low | unclear | unclear | low | low | low | B |