Agreement was assessed for whether the allocation ratio was specified, the method of randomisation, whether centre was used as a balancing factor and adjusted for in the analysis, and whether any prognostic variables were used as balancing factors and adjusted for in the analysis.
Risk of bias of randomised studies was assessed for generation of the allocation sequence, allocation concealment, blinding, and follow-up.
Each study was assessed for the adequacy of allocation concealment, blinding of outcome assessment, whether the analysis was conducted on an intention-to-treat basis, whether the outcomes were prospectively defined, and whether there were important differences between the two groups at baseline.
Risk of bias was assessed for the generation of the allocation sequence, allocation concealment, masking, incomplete outcome data, and sponsorship bias.
The following six components were assessed for each trial: generation of allocation sequence, allocation concealment, blinding (of participants, personnel, and outcome assessors), incomplete outcome data, selective outcome reporting, and other sources of bias.
17 Each study was assessed for random sequence generation, allocation concealment, blinding of participants, blinding of outcome assessment, incomplete outcome data, selective reporting, and other sources of bias.
Each report was assessed for the adequacy of allocation concealment, blinding, performance of an intention to treat analysis and the extent of loss to follow-up.
Research workers blind to allocation, assessed for eligibility and collected outcome measures using patients' self report questionnaires to minimise the effect of potential unblinding.
All self reported outcome measures and procedures were pilot tested, the data collection nurses were trained and assessed for blinding to group allocation, and our losses to follow-up were below 15%.
For pragmatic reasons, studies with mixed-sex and women-only samples that were used to derive comparison groups were assessed for quality based on the allocation concealment domain only.
