Table 1.

Quality assessment.

Study ID	Random sequence generation	Allocation concealment	Blinding of participants and personnel	Blinding of outcome data	Incomplete outcome data	Selective reporting	Other bias
Parellada et al. (28)	Low risk	Low risk	Low risk	Low risk	Low risk	Low risk	Unknow
Ooi et al. (29)	High risk	Unknow	High risk	Low risk	Low risk	Low risk	Unknow
Bent et al. (30)	Low risk	Low risk	Low risk	Low risk	Low risk	Low risk	Unknow
Bent et al. (31)	Low risk	Low risk	Low risk	Low risk	Low risk	Low risk	Unknow
Mankad et al. (32)	Low risk	Low risk	Unknow	Low risk	Low risk	Low risk	Unknow
Politi et al. (33)	High risk	High risk	Low risk	High risk	High risk	High risk	Unknow
Amminger et al. (34)	Unknow	Unknow	Low risk	Low risk	Low risk	Low risk	Unknow
Voigt et al. (35)	Low risk	Low risk	Low risk	Low risk	Low risk	Low risk	Unknow
Yui et al. (36)	Low risk	Low risk	Low risk	Low risk	Low risk	Low risk	Unknow
Doaei et al. (37)	Low risk	Low risk	Low risk	Low risk	Low risk	Low risk	Unknow
Javadfar et al. (38)	Low risk	Low risk	Low risk	Low risk	Low risk	Low risk	Unknow
Saad et al. (39)	Low risk	Low risk	Low risk	Low risk	Low risk	Low risk	Unknow
Saad et al. (20)	High risk	High risk	Low risk	Low risk	High risk	Low risk	Unknow
Duan (40)	High risk	High risk	Low risk	Low risk	High risk	High risk	Unknow
Kerley et al. (41)	Low risk	Low risk	Low risk	Low risk	Low risk	Low risk	Unknow
Feng et al. (42)	High risk	High risk	Low risk	Low risk	High risk	Low risk	Unknow
Mazahery et al. (43)	Low risk	Low risk	Low risk	Low risk	Low risk	Low risk	Unknow
Mazahery et al. (44)	Low risk	Low risk	Low risk	Low risk	Low risk	Low risk	Unknow
Mazahery et al. (45)	Low risk	Low risk	Low risk	Low risk	Low risk	Low risk	Unknow
Fang et al. (46)	Low risk	High risk	Low risk	Low risk	High risk	High risk	Unknow