Table 3.

Quality Assessment of the Included Studies.

Study	Random Sequence Generation	Allocation Concealment	Blinding of Participants and Personnel	Blinding of Outcome Assessment	Incomplete Outcome Data	Selective Outcome Reporting	Other Bias
Cao et al. (2005)	L	L	L	U	L	U	U
Deng (2008)	U	U	H	U	L	U	U
Ji et al. (2008)	U	U	H	U	L	U	U
Deng and Ding (2009)	L	U	H	U	L	U	U
Ma et al. (2009)	L	U	H	U	L	U	U
Qi et al. (2009)	U	U	H	U	L	U	U
Zhang et al. (2009)	U	U	H	U	L	U	U
Xie et al. (2010)	U	U	H	U	L	U	U
Kang et al. (2011)	U	U	H	U	L	U	U
Liu and Xue (2011)	U	U	H	U	L	U	U
Fan et al. (2012)	L	U	H	U	L	U	U
Gao et al. (2012)	U	U	H	U	L	U	U
Li et al. (2012)	U	U	H	U	L	U	U
Liu et al. (2012)	U	U	H	U	L	U	U
Sun et al. (2012)	U	U	H	U	L	U	U
Tao et al. (2012)	U	U	H	U	L	U	U
Yang (2012)	U	U	H	U	L	U	U
Lin et al. (2013)	U	U	H	U	L	U	U
Zhu et al. (2013)	U	U	H	U	L	U	U
Fu and Teng (2014)	L	U	H	U	L	U	U
Han (2014)	L	U	H	U	L	U	U
Lin and Wang (2014)	L	L	H	U	L	U	U
Tang et al. (2014)	L	U	H	U	L	U	U

L = low risk of bias; H = high risk of bias; U = unclear risk of bias.