Table 2 Risk of bias of included studies (n = 45)
No. | Study | External validity | Internal validity | Overall |
|---|---|---|---|---|
1 | Chen ND, 2012 | Moderate Risk | Moderate Risk | Moderate Risk |
2 | Ding D, 2015 | Low Risk | Low Risk | Low Risk |
3 | Guo GY, 2013 | Moderate Risk | Moderate Risk | Moderate Risk |
4 | Guo XY, 2013 | Moderate Risk | Moderate Risk | Moderate Risk |
5 | Hai S, 2011 | Moderate Risk | Moderate Risk | Moderate Risk |
6 | He L, 2015 | Low Risk | Moderate Risk | Moderate Risk |
7 | Hu R, 2012 | Moderate Risk | Moderate Risk | Moderate Risk |
8 | Huang R, 2008 | Low Risk | Low Risk | Low Risk |
9 | JIA J, 2013 | Low Risk | Low Risk | Low Risk |
10 | Jiang LJ, 2017 | Moderate Risk | Moderate Risk | Moderate Risk |
11 | Lao ML, 2011 | Moderate Risk | Moderate Risk | Moderate Risk |
12 | Li CP, 2014 | low Risk | Moderate Risk | Moderate Risk |
13 | Li X, 2013 | Moderate Risk | Moderate Risk | Moderate Risk |
14 | Li W, 2020 | low Risk | Low Risk | Low Risk |
15 | Liao B, 2012 | Moderate Risk | Moderate Risk | Moderate Risk |
16 | Liu H, 2018 | low Risk | Moderate Risk | Moderate Risk |
17 | Ma F, 2016 | Low Risk | Low Risk | Low Risk |
18 | Meng WQ, 2010 | Moderate Risk | Moderate Risk | Moderate Risk |
19 | Pan HY, 2012 | Moderate Risk | High Risk | High Risk |
20 | Pan ZD, 2012 | Low Risk | Moderate Risk | Moderate Risk |
21 | Peng Z, 2019 | Moderate Risk | High Risk | High Risk |
22 | Qin HY, 2014 | Low Risk | Low Risk | Low Risk |
23 | Qiu CJ, 2003 | Moderate Risk | Low Risk | Moderate Risk |
24 | Rao D, 2018 | Low Risk | Low Risk | Low Risk |
25 | Ren CF, 2013 | Moderate Risk | Low Risk | Moderate Risk |
26 | Song XZ, 2012 | Low Risk | Moderate Risk | Moderate Risk |
27 | Sosa AL, 2012 | Moderate Risk | Moderate Risk | Moderate Risk |
28 | Su C, 2013 | Moderate Risk | Moderate Risk | Moderate Risk |
29 | Sun Y, 2014 | Low Risk | Moderate Risk | Moderate Risk |
30 | Tang Z, 2007 | Low Risk | Moderate Risk | Moderate Risk |
31 | Tang MN, 2000 | Low Risk | Moderate Risk | Moderate Risk |
32 | Wang T, 2017 | Low Risk | Moderate Risk | Moderate Risk |
33 | Wang TT, 2017 | Low Risk | Low Risk | Low Risk |
34 | Wang YP, 2011 | Moderate Risk | Moderate Risk | Moderate Risk |
35 | Wang ZZ, 2013 | Moderate Risk | Moderate Risk | Moderate Risk |
36 | Wu L, 2016 | Moderate Risk | High Risk | High Risk |
37 | Wu Y, 2017 | Low Risk | Moderate Risk | Moderate Risk |
38 | Xiao SF, 2016 | Low Risk | Low Risk | Low Risk |
39 | Xu SJ, 2014 | Low Risk | Moderate Risk | Moderate Risk |
40 | Yin LY, 2010 | Low Risk | Moderate Risk | Moderate Risk |
41 | Yuan J, 2013 | Moderate Risk | Moderate Risk | Moderate Risk |
42 | Zhang XQ, 2014 | Low Risk | Low Risk | Low Risk |
43 | Zhong SY, 2018 | Moderate Risk | High Risk | High Risk |
44 | Zhou DS, 2011 | Moderate Risk | Low Risk | Moderate Risk |
45 | Zhu XQ, 2009 | Moderate Risk | Low Risk | Moderate Risk |