Table 2.

Methodological quality of the included studies according to the Risk of Bias 2.0 tool.

Included Study	D1	D2	D3	D4	D5	Overall
Jin 2004 [59]	Sc	H	H	L	Sc	H
Sun 2008 [60]	Sc	H	H	Sc	Sc	H
Shen 2009 [61]	L	H	H	L	Sc	H
Lin 2010 [62]	Sc	H	H	L	Sc	H
Wang 2010 [63]	L	H	H	L	Sc	H
Yan 2010 [64]	Sc	H	H	Sc	Sc	H
Wu 2011 [65]	Sc	H	H	L	Sc	H
Gao 2012 [66]	Sc	H	H	L	Sc	H
Gong 2013 [67]	Sc	H	H	L	Sc	H
Han 2013 [68]	L	H	H	Sc	Sc	H
Zhang 2013a [69]	L	H	H	L	Sc	H
Zhang 2013b [70]	Sc	H	H	L	Sc	H
Guo 2014 [71]	Sc	H	H	Sc	Sc	H
Yang 2014a [73]	Sc	H	H	Sc	Sc	H
Yang 2014b [72]	L	H	H	Sc	Sc	H
Qi 2015 [74]	Sc	H	H	L	Sc	H
Wang 2015 [75]	Sc	H	H	Sc	Sc	H
Xue 2015 [76]	L	H	H	L	Sc	H
Guo 2016 [77]	L	H	H	L	Sc	H
Han 2016 [78]	Sc	H	H	L	Sc	H
Lan 2016 [79]	H	H	H	L	Sc	H
Mo 2016 [82]	L	H	H	Sc	Sc	H
Wang 2016 [83]	L	H	H	Sc	Sc	H
Li 2016a [80]	L	H	H	L	Sc	H
Zhang 2016a [85]	L	H	H	L	Sc	H
Li 2016b [81]	Sc	H	H	L	Sc	H
Zhang 2016b [84]	L	H	H	L	Sc	H
Chen 2017 [86]	L	H	H	L	Sc	H
Shi 2017 [87]	Sc	H	H	L	Sc	H
Wang 2017 [88]	L	H	H	L	Sc	H
Chen 2018 [89]	L	H	H	Sc	Sc	H
Dai 2018 [90]	H	H	H	L	Sc	H
Hu 2018 [92]	Sc	H	H	L	Sc	H
Huang 2018 [93]	L	H	H	L	Sc	H
She 2018 [94]	L	H	H	L	Sc	H
Xin 2018 [95]	H	H	H	Sc	Sc	H
Gao 2019 [91]	Sc	H	H	L	Sc	H
Wu 2019 [99]	L	H	H	L	Sc	H
Yi 2019 [100]	L	H	H	L	Sc	H
Ji 2019 [96]	L	H	H	Sc	Sc	H
Liu 2019a [97]	Sc	H	H	L	Sc	H
Liu 2019b [98]	Sc	H	H	Sc	Sc	H
Chen 2021 [101]	Sc	H	Sc	L	Sc	H
Hou 2021 [102]	Sc	H	H	L	Sc	H
Li 2021 [103]	L	H	H	L	Sc	H
Wang 2021a [105]	L	H	H	L	Sc	H
Wang 2021b [104]	L	H	H	L	Sc	H
Zhang 2021 [106]	H	H	H	L	Sc	H

D1–D5: five domain criteria; D1: bias arising from the randomization process; D2: bias due to deviations from intended interventions; D3: bias due to missing outcome data; D4: bias in the measurement of the outcome; D5: bias in the selection of the reported results; H: high risk of bias; L: low risk of bias; Sc: some concerns.