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 |