Table 2.
Risk of bias in included studies
| Study/year | Sequence generation | Allocation concealment | Blinding of participants and personnel | Blinding of outcome assessors | Incomplete outcome data | Selective outcome reporting | Other source of bias |
|---|---|---|---|---|---|---|---|
| Colombo/2008 | Low | Unclear | High | Unclear | Low | Unclear | Unclear |
| Xirouchaki/2008 | Low | Unclear | High | Unclear | Low | Low | Low |
| Spahija/2010 | Unclear | Unclear | High | Unclear | Unclear | Unclear | Unclear |
| Patroniti/2012 | Unclear | Unclear | High | Unclear | Low | Unclear | Unclear |
| Elganady/2014 | Low | Low | High | Unclear | Unclear | Low | Low |
| Doorduin/2015 | Unclear | Unclear | High | Unclear | Unclear | Low | Unclear |
| Schmidt/2015 | Low | Unclear | High | Unclear | Unclear | Low | Unclear |
| Bosma/2016 | Low | Unclear | High | Unclear | Low | Unclear | Low |
| Carteaux/2016 | Low | Unclear | High | High | Low | Low | Unclear |
| Demoule/2016 | Low | Low | High | Low | High | Low | Low |
| Di mussi/2016 | Unclear | Unclear | High | Unclear | High | High | Unclear |
| Kuo/2016 | Unclear | Unclear | High | Unclear | Low | Low | Unclear |
| Costa/2017 | Low | Low | High | Unclear | Low | Low | Unclear |
| Ferreira/2017 | Low | Low | High | Low | Low | Low | Unclear |
| Botha/2018 | Low | Low | High | High | Low | Low | High |