Table 3 Risk of bias assessment of the randomized controlled trials
RCT | Random sequence generation | Allocation concealment | Blinding of participants and personnel | Blinding of outcome assessment | Incomplete outcome data | Selective reporting | Other bias |
|---|---|---|---|---|---|---|---|
Feng et al | Low risk | Unclear risk | High risk | Low risk | Low risk | Low risk | Unclear risk |
Cui et al | Low risk | Low risk | High risk | Low risk | Low risk | Low risk | Unclear risk |
Wang et al | Low risk | Unclear risk | High risk | Unclear risk | Low risk | Low risk | Unclear risk |
Hyun et al | Low risk | Low risk | High risk | Unclear risk | Low risk | Low risk | Unclear risk |