Risks for bias in included RCTs. We assessed study risk for bias according to recommendations from the Cochrane Collaboration . *Whether the study reported methods of randomization sufficiently to meet current CONSORT guidelines for true random allocation of participants . ^ Whether the study reported methods to conceal allocation sufficiently to determine whether the chosen intervention for a participant could have been predicted in advance. † Whether the study reported methods by which patients, staff or assessors were prevented from knowing the intervention given to each participant. ‡ Whether the study described loss-to-follow up figures.