Table 2 Summary risk of bias for each trial
Trial | Randomisation | Allocation concealment | Blinding – primary outcomes | Blinding – secondary outcomes | Incomplete outcome | Selective outcome reporting | Contamination | Other – general bias |
|---|---|---|---|---|---|---|---|---|
Abdulrahman 2017 | Low | Low | Low | High | Low | Low | Unclear | Unclear |
Belzer 2014 | Low | Unclear | Low | High | High | Low | Unclear | High |
Da Costa 2012 | Low | Unclear | Low | High | High | Low | Unclear | Unclear |
Haberer 2016 | Low | Unclear | Low | Low | Low | Low | Unclear | Unclear |
Hardy 2011 | Low | Unclear | Low | Low | High | Low | Unclear | Unclear |
Huang 2013 | Low | Low | Low | High | High | Unclear | Unclear | Unclear |
Ingersoll 2015 | Low | Low | Low | Low | Low | Low | Unclear | Low |
Kalichman 2011 | Low | Unclear | Low | Unclear | Low | Low | Unclear | Unclear |
Kebaya 2014 | Unclear | Unclear | Unclear | Unclear | Unclear | Unclear | Unclear | Unclear |
Lester 2010 | Low | Low | Low | High | High | Low | High | Unclear |
Maduka 2013 | Low | Low | Low | High | Low | Low | Low | Unclear |
Mbuagbaw 2012 | Low | Low | Low | High | High | Low | Unclear | Unclear |
Nsagha 2016 | Low | Unclear | Unclear | High | Unclear | Low | Unclear | Unclear |
Orrell 2015 | Low | Low | Low | Low | Low | High | Unclear | Unclear |
Perera 2014 | Unclear | Unclear | Low | High | Low | Unclear | Unclear | Unclear |
Pop-Eleches 2011 | Low | Unclear | Low | Low | Low | Unclear | Unclear | Unclear |
Sabin 2015 | Low | Low | Low | Low | Low | Low | Unclear | Unclear |
Shet 2014 | Low | Low | Low | Low | Low | Low | Low | Unclear |
Uzma 2011 | Low | Unclear | Low | High | High | High | Unclear | Unclear |