Table 2.
Study | Randomisation process | Deviations from intended interventions | Missing outcome data | Measurement of outcome | Selection of reported result | Overall bias |
---|---|---|---|---|---|---|
Alpay and Turhan (2001) | High | High | Low | High | Some concerns | High |
Flores-Ramos et al. (2003) | Some concerns | Low | Low | Low | High | High |
Freeman et al. (1999) | Some concerns | Low | Low | Low | Some concerns | Some concerns |
Freeman et al. (2002) | High | Low | Low | Some concerns | Some concerns | High |
Freeman et al. (2004) | Low | Low | Low | Low | Some concerns | Some concerns |
Landén et al. (2007) | Low | Low | Low | Low | Some concerns | Some concerns |
Wikander et al. (1998) | Low | Low | Low | Low | Some concerns | Some concerns |
Wu et al. (2008) | High | Low | Low | Low | Some concerns | High |