A data extraction sheet was constructed to record information on study characteristics, patient characteristics, and predefined outcomes. Risk of bias was assessed using the Cochrane Collaboration’s13 risk-of-bias tool and criteria for judging risk of bias. The domains assessed were random sequence generation and allocation concealment (selection bias), blinding of study participants and personnel (performance bias), blinding of outcome assessment (detection bias), incomplete outcome data (attrition bias), selective reporting (reporting bias), and other bias.