Table 3.

Risk of bias within studies.

Study	1	2	3	4	5	Overall GRADE
Baek et al. [28]	Some concerns	Low risk	Low risk	Low risk	Some concerns	High risk
Campos-Mesa et al. [29]	High risk	Low risk	Some concerns	Low risk	Some concerns	High risk
Cho & Roh [30]	Some concerns	Low risk	Low risk	Low risk	Some concerns	Some concerns
Ciaccioni et al. [31]	High risk	Low risk	Some concerns	Low risk	Some concerns	High risk
Combs et al. [32]	Some concerns	Low risk	Low risk	Low risk	Some concerns	Some concerns
Cromwell et al. [33]	High risk	Low risk	Some concerns	Low risk	Some concerns	High risk
Witte et al. [34]	Some concerns	Low risk	Low risk	Low risk	Some concerns	Some concerns
Youm et al. [35]	Some concerns	Low risk	Low risk	Low risk	Some concerns	Some concerns

1: randomization process. 2: deviations from intended intervention-effects of assignment to intervention. 3: missing outcome. 4: measurement of the outcome. 5: selection of the reported result. GRADE: Grading of Recommendations, Assessment, Development, and Evaluation. Low risk: low risk of bias. High risk: high risk of bias.