Table 2.
Synthesis of Risk Assessment of Included Studies
| Study | Random sequence generation (selection bias) | Allocation concealment (selection bias) | Baseline characteristics | Baseline outcome measurement | Blinding of participants and staff (performance bias) | Blinding of outcome assessment (detection bias) | Incomplete outcome data (attrition bias) | Selective reporting (reporting bias) | Contamination | Bias due to insufficient power | |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Chan et al. (2009) | Low | Low | Low | Low | Unclear | Low | Low | Unclear | Low | Low | |
| Dierick-van Daele et al. (2009) | Low | Low | Low | Unclear | Unclear | Unclear | Low | Unclear | Low | Unclear | |
| Kamps et al. (2003) | Low | Low | Low | Low | Unclear | Unclear | High | Unclear | Low | High | |
| Kinnersley et al. (2000) | Low | Low | Low | Low | Unclear | Unclear | Low | Low | Low | Low | |
| Krichbaum (2007) | Low |
Low |
Low | Unclear | Unclear | Low | High | Unclear | High | High | |
| Kuethe et al. (2011) | Low |
Low | Low | Low | Unclear | Unclear | Low | Low | Low | Low | |
| Mundinger et al. (2000) | Unclear | Unclear | Low | Low | Unclear | Unclear | High | Unclear | High | Low | |
| Ndosi et al. (2014) | Low | Low | Low | Low | Unclear | Low | Unclear | Low | Low | Low | |
| Ryden et al. (2000) | Unclear | Unclear | Unclear | Unclear | Unclear | Unclear | High | Low | Low | Unclear | |
| Stables et al. (2004) | Low | Low | Unclear | Unclear | Unclear | Unclear | Unclear | Low | Low | Low | |
| van Zuilen et al. (2011) | Low | Low | Low | Low | Unclear | Low | Low | Low | Low | Unclear | |
| Venning et al. (2000) | Low | Low | Low | Unclear | Unclear | Unclear | High | Unclear | Unclear | Unclear | |
| Williams et al. (2005) | Low | Low | Low | Low | Unclear | Unclear | Low | Low | Unclear | Low | |