Table 1a.

Sources of risk of bias.

Bias Domain	Source of Bias	Answers
Selection	Was the method of randomization adequate?	Yes/No/Unsure
Selection	Was the treatment allocation concealed?	Yes/No/Unsure
Performance	Was the patient blinded to the intervention?	Yes/No/Unsure
Performance	Was the care provider blinded to the intervention?	Yes/No/Unsure
Detection	Was the outcome assessor blinded to the intervention?	Yes/No/Unsure
Attrition	Was the drop-out rate described and acceptable?	Yes/No/Unsure
Attrition	Were all randomized participants analyzed in the group to which they were allocated?	Yes/No/Unsure
Reporting	Are reports of the study free of suggestion of selective outcome reporting?	Yes/No/Unsure
Selection	Were the groups similar at baseline regarding the most important prognostic indicators?	Yes/No/Unsure
Performance	Were cointerventions avoided or similar?	Yes/No/Unsure
Performance	Was the compliance acceptable in all groups?	Yes/No/Unsure
Detection	Was the timing of the outcome assessment similar in all groups?	Yes/No/Unsure
Other	Are other sources of potential bias unlikely?	Yes/No/Unsure