Fig. 2

The risk-of-bias assessments of the included studies. The risk-of-bias assessments of the included studies. Random sequence generation (selection bias), allocation concealment (selection bias), blinding of participants and personnel (performance bias), blinding of outcome assessment (detection bias), incomplete outcome data (attrition bias), selective reporting (reporting bias), and other bias were assessed by Review Manager 5.4 as “low,” “high,” or “unclear” risk. Green color indicated low risk of bias, yellow color indicated unclear risk of bias, and red color indicated high risk of bias. About 71% studies have low risk of selection bias, and 29% studies have unclear risk of selection bias. About 41% studies have low risk of performance bias, and 51% studies have unclear risk of performance bias. About 29% studies have low risk of detection bias, and 71% studies have unclear risk of detection bias. All studies have low risk of attrition bias and reporting bias. About 47% studies have low risk of other bias, and 53% studies have high risk of other bias