Table 2:

Risk of bias for studies included in the systematic review

Study, yearDomain 1: Study participationDomain 2: Study attritionDomain 3: Prognostic factor measurementDomain 4: Outcome measurementDomain 5: Study confoundingDomain 6: Statistical analysis and reportingOverall risk of bias
Barnes et al.,21 2008HighLowLowLowModerateLowHigh
Moss et al.,1 2008LowLowLowLowModerateLowModerate
Cohen et al.,20 2010HighLowLowLowModerateLowHigh
Moss et al.,26 2010ModerateLowLowLowLowLowModerate
Da Silva Gane et al.,30 2013LowLowLowLowModerateLowModerate
Pang et al.,22 2013LowModerateLowLowModerateLowModerate
Reilly et al.,23 2013ModerateLowLowLowModerateLowModerate
Khan et al.,24 2014LowLowLowLowModerateLowModerate
Moroni et al.,25 2014ModerateLowLowLowLowLowModerate
Feyi et al.,27 2015LowLowLowModerateHighLowHigh
Vick et al.,28 2015ModerateModerateLowLowLowLowModerate
Gerlach et al.,33 2016LowLowLowLowLowLowLow
Amro et al.,31 2016LowLowLowLowModerateLowModerate
Lefkowits et al.,35 2016LowLowLowLowLowLowLow
Carmen et al.,32 2016LowLowLowLowModerateLowModerate
Lakin et al.,34 2016HighLowLowLowLowLowHigh