Table 2.

Quality assessment of the studies included in the review

Authors (years) Reference	Bias due to confounders	Bias due to the selection of participants	Bias due to the measurement of intervention	Bias due to missing data	Incomplete outcome data	Free of selective reporting	Other sources of bias
Li et al. (7)	Yes	Yes	Yes	Yes	Yes	No	Yes
Li et al. (11)	No	No	No	No	No	Unclear	No
Guo et al. (14)	No	No	No	Yes	No	Yes	No
Wang et al. (12)	No	No	Yes	Yes	Yes	Unclear	Yes
Ellenrieder et al. (16)	No	No	No	No	No	Yes	No
Majewski et al. (19)	No	No	No	No	No	No	No
Xue-Zhong et al. (17)	Yes	Yes	No	No	No	No	Yes
Liu et al. (18)	No	No	No	No	No	Yes	Unclear
Zhuo et al. (13)	No	No	No	No	No	Yes	No
Przybył et al. (47)	Yes	No	No	No	No	Yes	Unclear
O’Leary et al. (48)	Yes	Yes	Yes	Yes	No	Yes	No
Sekiya et al. (15)	No	No	No	No	No	Yes	No
Ruch et al. (30)	No	No	No	No	No	Yes	No