Risk of bias in included studies
| Study | Random sequence generation | Allocation concealment | Blind participants and personnel | Blind outcome assessment | Incomplete outcome data | Selective reporting |
| Burke et al18 | Unclear | Unclear | Low | Unclear | Low | High |
| Feighner and Overo19 | Unclear | Unclear | Low | Unclear | Low | High |
| Frank et al20 | Unclear | Unclear | Low | Unclear | Low | High |
| Gastpar et al21 | Low | Unclear | Low | Unclear | Low | High |
| Lepola et al22 | Unclear | Unclear | Low | Unclear | Low | High |
| Mendels et al23 | Unclear | Unclear | Unclear | Unclear | Low | High |
| Montgomery et al24 | Unclear | Unclear | Low | Unclear | High | High |
| Stahl25 | Unclear | Unclear | Low | Unclear | Low | High |








