Table 2.
Assessment of the risk of bias
| Study | Year of publication | Random sequence generation | Allocation concealment |
Defined inclusion/ exclusion |
Blinding of participants and/ or personnel |
Blinding of outcome assessment |
Incomplete outcome data | Selective reporting |
|---|---|---|---|---|---|---|---|---|
| Juodzbalys et al. [30] | 2008 | N/A | N/A | + | N/A | N/A | + | + |
| Schlee et al. [33] | 2009 | + | + | + | N/A | N/A | + | + |
| Horowitz et al. [34] | 2009 | N/A | N/A | + | N/A | N/A | + | + |
| Jung et al. [35] | 2018 | - | - | + | N/A | N/A | + | + |
| Kim et al. [62] | 2017 | N/A | N/A | + | N/A | N/A | + | + |
+ = low risk; N/A = unclear risk; - = high risk.