Table 3.

Quality assessment of included randomized controlled trials.

Included trials	Random sequence generation	Allocation concealment	Blinding of participants and personnel	Blinding of outcome assessment	Incomplete outcome data	Selective reporting	Other sources of bias	Risk of bias
Wang et al., 1998 [63]	Unclear	Unclear	Unclear	Unclear	Yes	No	Unclear	High
Ren and Zhao, 2012 [64]	Table of random number	Unclear	Unclear	Unclear	Yes	No	Unclear	Unclear
Fu, 2005 [65]	Unclear	Unclear	Unclear	Unclear	Yes	No	Unclear	High
Qin, 2010 [66]	Unclear	Unclear	Unclear	Unclear	Yes	No	Unclear	High
Hu et al., 2009 [67]	Simple random sampling	Unclear	Yes	Unclear	No	No	Unclear	Unclear
Sun and Huang, 2007 [68]	Unclear	Unclear	Unclear	Unclear	No	No	Unclear	High
Wang et al., 2008 [69]	Unclear	Unclear	Unclear	Unclear	Yes	No	Unclear	High
Fang et al., 2008 [70]	Unclear	Unclear	Unclear	Unclear	No	No	Unclear	High
Li, 2006 [71]	Unclear	Unclear	Unclear	Unclear	Yes	No	Unclear	High
Liu, 2011 [72]	Unclear	Unclear	Unclear	Unclear	Yes	No	Unclear	High
Liu et al., 2009[73]	Unclear	Unclear	Unclear	Unclear	Yes	No	Unclear	High
Chen, 2009 [74]	Drawing	Unclear	Unclear	Unclear	No	No	Unclear	Unclear
Zhang and Yang, 2011 [75]	Table of random number	Unclear	Unclear	Unclear	Yes	No	Unclear	Unclear
Liu and Li, 2011 [76]	Unclear	Unclear	Unclear	Unclear	No	No	Unclear	High
Wei, 2012 [77]	Unclear	Unclear	Unclear	Unclear	Yes	No	Unclear	High
Li, 2011 [78]	Unclear	Unclear	Unclear	Unclear	Yes	No	Unclear	High
Lin and Liu, 2010 [79]	Unclear	Unclear	Unclear	Unclear	Yes	No	Unclear	High
Zhou and Zhang, 2011 [80]	Table of random number	Unclear	Unclear	Unclear	No	No	Unclear	Unclear
Chen, 2008 [81]	Drawing	Unclear	Unclear	Unclear	No	No	Unclear	Unclear
Du, 2012 [82]	Unclear	Unclear	Unclear	Unclear	Yes	No	Unclear	High
Cheng, 2010 [83]	Unclear	Unclear	Unclear	Unclear	Yes	No	Unclear	High
Zhu, 2009 [84]	Table of random number	Unclear	Unclear	Unclear	No	No	Unclear	Unclear