Table 2.

Methodological quality of included randomized clinical trials

First author, year[Ref.]	Generation of allocation sequence	Allocation concealment	Blinding	Methodologicalquality
Han, 2010[22]	Unclear	Unclear	Unclear	Low
Zhang, 2010[21]	Unclear	Unclear	Unclear	Low
Han, 2009[23]	Unclear	Unclear	Unclear	Low
Su, 2009[24]	Unclear	Unclear	Unclear	Low
Xu, 2009[25]	Unclear	Adequate	Adequate	High
Shi, 2009[26]	Adequate	Adequate	Adequate	High
Yang, 2008[27]	Adequate	Unclear	Unclear	Low
Guo, 2008[28]	Adequate	Unclear	Unclear	Low
Xiang, 2007[29]	Adequate	Unclear	Unclear	Low
Feng, 2007[30]	Not done	Not done	Not done	Low
Li, 2006[31]	Not done	Not done	Not done	Low
Li, 2006[32]	Not done	Not done	Not done	Low
Han, 2005[33]	Not done	Not done	Not done	Low
Shi, 2005[34]	Adequate	Unclear	Unclear	Low
Li, 2003[35]	Adequate	Unclear	Unclear	Low