Table 4 QUIPS scores showing risk of bias
| Â | Study participation | Study attrition | Prognostic factor measurement | Outcome measurement | Study confounding | Statistical analysis & reporting | Overall Rating |
|---|---|---|---|---|---|---|---|
Gobbi and Francisco | Low | High | Moderate | Moderate | High | Moderate | High |
Heijne, Äng and Werner | High | Low | Moderate | Low | High | Moderate | High |
Hetsroni et al., | Moderate | Moderate | Moderate | Low | High | Moderate | Moderate |
Jurkonis, Gudas and Smailys | Moderate | High | Low | Low | High | Moderate | High |
Liptak and Angel | Low | Low | Moderate | Moderate | High | Moderate | Moderate |
McGrath et al., | Moderate | High | Moderate | Moderate | High | Moderate | High |
Sonesson et al., | Low | High | Moderate | Moderate | Moderate | Moderate | Moderate |
Thomeé et al., | High | High | Moderate | Low | Moderate | Moderate | High |