Table 2.

Quality assessment of included randomized controlled trials.

No.	Included trials	Random sequence generation	Allocation concealment	Blinding	Incomplete outcome data	Selective reporting	Other sources of bias
1	Zhou (2009) [24]	Unclear	Unclear	High risk	Low risk	Low risk	Unclear
2	Zhang (2012) [25]	Unclear	Unclear	High risk	Low risk	Low risk	Unclear
3	Yu (2008) [26]	Unclear	Unclear	High risk	Low risk	Low risk	Unclear
4	Xia (2008) [27]	Unclear	Unclear	High risk	Low risk	Low risk	Unclear
5	Xiong et al. (2003) [28]	Unclear	Unclear	High risk	Low risk	Low risk	Unclear
6	Wu (2016) [29]	Low risk, table of random numbers	Low risk, unification of drug packaging	High risk	Low risk	Low risk	Unclear
7	Wen (2011) [30]	Unclear	Unclear	High risk	Low risk	Unclear	Unclear
8	Tan (2014) [31]	Unclear	Unclear	High risk	Low risk	Low risk	Unclear
9	Liu et al. (2014) [32]	Unclear	Unclear	High risk	Low risk	Unclear	Unclear
10	Li (2004) [33]	Low risk, table of random numbers	Unclear	High risk	Low risk	Low risk	Unclear
11	Lei (2011) [34]	Unclear	Unclear	High risk	Low risk	Low risk	Unclear
12	Jin (2014) [35]	Low risk, table of random numbers	Unclear	High risk	Low risk	Low risk	Unclear
13	Cui et al. (2011) [36]	Unclear	Unclear	High risk	Low risk	Low risk	Unclear
14	Zhang (2004) [37]	Unclear	Unclear	High risk	Low risk	Low risk	Unclear