Table 3 Quality assessment of the included studies
First author (year) | Selection bias (random sequence generation) | Selection bias (allocation concealment) | Performance bias (blinding of participants and personnel) | Detection bias (blinding of outcome assessment) | Attrition bias (incomplete outcome data) | Reporting bias (selective reporting) |
|---|---|---|---|---|---|---|
Saba (2013) [43] | Y | Unclear | Y | Unclear | Y | Y |
Khan (2012) [42] | Y | Y | Y | Y | Y | Y |
Bai (2011) [44] | N | N | Unclear | Y | Y | Y |