Table 2.

Quality assessment.

Author	Random sequence generation	Allocation concealment	Blinding of participants and personnel	Blinding of outcome assessment	Incomplete outcome data
Brohet et al. (13)	L	U	L	U	L
Cannon et al. (14)	U	U	U	U	L
Hibi et al. (15)	L	U	H	L	L
Joshi et al. (16)	L	U	U	U	L
Masuda et al. (17)	L	L	H	H	L
Ran et al. (18)	L	U	H	U	L
Ren et al. (19)	L	U	U	U	L
Ueda et al. (20)	L	U	H	L	L
Wang et al. (21)	U	U	U	U	L
Wang et al. (22)	L	U	U	U	L
West et al. (23)	L	U	L	L	L
Zou (24)	U	U	U	U	L
El-Tamalawy et al. (25)	L	U	L	L	L
Klassen et al. (26)	L	U	L	L	L
Oh et al. (27)	L	U	L	L	L
Pinto et al. (28)	L	U	L	L	L
Blom et al. (29)	L	U	L	L	L
Mikkle et al. (10)	L	U	L	L	L
Jung et al. (11)	L	U	L	L	L
Kovarnik et al. (12)	L	H	L	L	L

L, low; H, high; U, unclear.