Table 3: Risk of bias summary. +: low risk of bias; ±: unclear risk of bias; −: high risk of bias.

Random sequence generationAllocation concealmentBlinding of participants and personnelBlinding of outcome assessmentIncomplete outcome dataSelective reportingOther bias

Alcantara et al.++±+++
Arezzo et al.+++++++
Cheung et al.++±+++
Ghazal et al.++±+++
Ho et al.++±+++
Pirlet et al.++±+++
van Hooft et al.+++++++