Risk-of-bias review of included studies
| Study | Random sequence generation (selection bias) | Allocation concealment (selection bias) | Blinding (performance bias and detection bias) | Incomplete outcome data (attrition bias) | Selective reporting (reporting bias) | Other bias |
|---|---|---|---|---|---|---|
| Al-Nakib et al. (26) | Unclear | Unclear | Low | Low | High | High |
| Douglas et al. (27) | Unclear | Unclear | Low | High | Unclear | High |
| Eby et al. (28) | Unclear | Unclear | Low | High | Low | High |
| Farr et al. (A) (29) | Low | Unclear | Low | Unclear | High | Unclear |
| Farr et al. (B) (29) | Low | Unclear | Low | Unclear | Unclear | Unclear |
| Godfrey et al. (30) | Low | Low | Low | High | Unclear | Unclear |
| Kurugöl et al. (31) | Low | Unclear | Low | Low | Low | Low |
| Kurugöl et al. (32) | Low | Low | Low | Low | Low | Low |
| Macknin et al. (33) | Low | Low | Low | Low | Low | Low |
| Mossad et al. (34) | Low | Low | Low | Low | Low | Unclear |
| Petrus et al. (34) | Unclear | Unclear | Low | Low | Unclear | Unclear |
| Prasad et al. (36) | Low | Low | Low | Low | Low | Low |
| Prasad et al. (37) | Low | Low | Low | Low | Low | Low |
| Smith et al. (38) | Unclear | Unclear | Low | High | High | Unclear |
| Turner et al. (A) (24) | Unclear | Unclear | Low | High | Low | Unclear |
| Turner et al. (B) (24) | Unclear | Unclear | Low | High | Low | Unclear |
| Weismann et al. (39) | Unclear | Unclear | Low | High | High | Unclear |