Table 2.
Risk of bias
| Review | Phase 2 | Phase 3 | |||
| 1. study eligibility criteria | 2. identification and selection of the studies | 3. data collection and study appraisal | 4. synthesis and findings | Risk of bias in the systematic reviews included | |
| Abbasi et al18 | ☺ | ☹ | ☹ | ☺ | ☹ |
| Barber et al19 | ☺ | ☹ | ☹ | ☺ | ☹ |
| Beswick et al29 | ☺ | ☺ | ☺ | ☺ | ☺ |
| Collins et al35 | ☺ | ☹ | ☹ | ☺ | ☺ |
| Cortes-Bergoderi et al24 | ☺ | ☹ | ☹ | ☺ | ☹ |
| Damen et al28 | ☹ | ☹ | ☺ | ☺ | ☺ |
| Damen et al31 | ☺ | ☺ | ☺ | ☺ | ☺ |
| Echouffo-Tcheugui et al33 | ☺ | ☺ | ☹ | ☺ | ☺ |
| Echouffo-Tcheugui et al30 | ☺ | ? | ☺ | ☺ | ? |
| Fowkes et al26 | ☺ | ☺ | ☹ | ? | ? |
| Hu et al21 | ? | ? | ? | ☹ | ? |
| Noble et al22 | ☺ | ☺ | ☹ | ☺ | ☺ |
| Siontis et al27 | ☺ | ☹ | ☺ | ☺ | ☺ |
| Sun et al32 | ☹ | ☹ | ☹ | ☺ | ☹ |
| Tzoulaki et al25 | ☺ | ☹ | ☺ | ☺ | ☺ |
| Yoshizawa et al23 | ☺ | ☺ | ☹ | ☺ | ☺ |
☺=low risk; ☹=high risk; ?=unclear risk.
ROBIS, Risk Of Bias In Studies tool; SRs, Systematic Revews.