Risk of bias of non-randomised comparative studies using modified Newcastle-Ottawa Scale
| Study | Participants selected from same cohort | Comparability of participants | Assessment of outcome | Incomplete data | Selective reporting |
|---|---|---|---|---|---|
| Yoon et al26 | Low risk | Low risk | High risk | Low risk | Low risk |
| Hayashi et al25 | Low risk | Low risk | High risk | Low risk | Low risk |
| El Matri et al20 | Low risk | Low risk | High risk | Low risk | Unclear |
| Dethorey et al21 | Low risk | Unclear | High risk | High risk | High risk |
| Yoon et al28 | Low risk | Low risk | Unclear | Low risk | Low risk |
| Lai et al29 | Low risk | Low risk | Unclear | Low risk | Low risk |
| Ikuno et al30 | High risk | Low risk | High risk | Low risk | Low risk |
| Baba et al31 | Low risk | Low risk | High risk | Low risk | Low risk |
| Kang and Koh32 | Low risk | Low risk | High risk | Low risk | Low risk |
| Cornish et al34 | Low risk | Unclear | High risk | Low risk | Low risk |