Table 4 Risk of bias assessment of randomised controlled studies
stduy | Selection bias | Performance bias | Detection bias | Attrition bias | Reporting bias | Other bias | |
|---|---|---|---|---|---|---|---|
Item 1 | Item 2 | Item 3 | Item 4 | Item 5 | Item 6 | Item 7 | |
Lee 2018 [22] | Low risk | Unclear risk | Unclear risk | Unclear risk | Low risk | Unclear risk | Unclear risk |
Li 2014 [23] | Unclear risk | Unclear risk | Unclear risk | Unclear risk | Low risk | Unclear risk | Unclear risk |
Raj 2011 [24] | Unclear risk | Unclear risk | High risk | High risk | Low risk | Unclear risk | Unclear risk |
Liao 2017 [25] | Unclear risk | Unclear risk | Unclear risk | Unclear risk | Low risk | Unclear risk | Unclear risk |