Assessment of risk of bias in included studies

Two review authors (of KR, LE, DW, AV, AD, LH) independently assessed risk of bias for each study using the criteria outlined in the Cochrane Handbook for Systematic Reviews of Interventions [32]. We resolved any disagreements by discussion or by involving another author (KR). We assessed the risk of bias according to the following domains: random sequence generation, allocation concealment, blinding of participants and personnel, blinding of outcome assessment, incomplete outcome data, selective outcome reporting and other bias. We graded each potential source of bias as high, low or unclear.