Table 2.

Risk of bias of the included studies

Study	A	B	C	D	E	F	G	H	I	J	Total
Abbas et al. [50]	+	+	–	+	?	+	?	+	+	?	6
Amini-Nik et al. [17]	+	+	–	–	?	?	?	+	+	?	4
de Andrade et al. [41]	+	+	–	–	?	?	+	+	+	?	5
Aryan et al. [45]	+	+	–	–	?	+	?	+	+	?	5
Bliley et al. [38]	+	+	–	–	?	?	+	+	+	?	5
Babakhani et al. [42]	?	+	–	–	?	?	?	+	+	?	3
Caliari-Oliveira et al. [28]	?	+	–	–	?	?	+	+	+	?	4
Chang et al. [39]	?	+	–	–	?	?	?	+	+	?	3
Feng et al. [37]	?	+	–	–	?	?	?	+	+	?	3
Foubert et al. [36]	?	+	–	–	?	?	+	+	+	?	4
Foubert et al. [52]	?	+	–	–	?	?	+	+	+	?	4
Franck et al. [16]	?	+	–	–	?	?	?	+	+	?	3
Imam et al. [44]	?	+	–	–	?	?	+	+	+	?	4
Li et al. [29]	+	+	–	–	?	?	?	+	+	?	4
Liu et al. [47]	+	+	–	–	?	+	+	+	+	?	6
Mahmood et al. [46]	?	+	–	–	?	+	?	+	+	?	4
Xue et al. [43]	?	+	–	–	?	?	?	+	+	?	3
Yang et al.—1 [51]	?	+	–	–	+	?	+	+	+	?	5
Yang et al.—2 [40]	?	+	–	+	+	?	+	+	+	?	6
Zhang et al. [48]	+	+	–	–	?	?	?	+	+	?	4
Zhou et al.—1 [30]	+	+	–	–	?	+	+	+	+	?	6
Zhou et al.—2 [49]	?	+	–	–	?	+	?	+	+	?	4

Note: Studies fulfilling the criteria of the following: A, sequence generation; B, baseline characteristics; C, allocation concealment; D, random housing; E, blinding of investigators; F, random animals assessment; G, blinding of outcome assessor; H, incomplete outcome data; I, selective outcome reporting; and J, other sources of bias