Assessment of risk of bias in the included studies
We independently assessed the risk of bias in the eligible studies according to the criteria described in the Cochrane Handbook version 5.1.0, which includes random sequence generation, allocation concealment, blinding of participants and personnel, blinding of the outcome assessment, incomplete outcome data, selective reporting, and other sources of bias [17]. The quality of the study was classified as low, unclear or high risk of bias. If necessary, we contacted the authors of eligible trials for clarification. Any differences in opinion were resolved by discussion or arbitration involving a third author