Table 3 Quality of the studies
Study | Sequence generation | Allocation concealment | Blinding | Incomplete outcome data | Selective outcome reporting | Free of other bias |
|---|---|---|---|---|---|---|
Ashari et al. 2016 | + | + | + | + | + | + |
Hirase et al. 2015 | ? | + | ? | + | + | ? |
Hwang et al. 2016 | + | + | + | + | + | + |
Kamai et al. 2015 | ? | ? | ? | + | + | ? |
Kim et al. 2014 | + | ? | + | + | + | ? |
Lee et al. 2013 | + | + | ? | + | + | ? |
Leung et al. 2014 | + | + | + | + | + | ? |
Ng et al. 2015 | + | + | + | + | + | ? |
Ohtake et al. 2013 | – | ? | – | ? | + | ? |
Yamada et al. 2012 | + | + | ? | ? | + | ? |
Yamada et al. 2013 | ? | ? | + | ? | + | ? |