Table 1.

Overall quality assessment of included randomized controlled trials based on the Cochrane risk of bias tool.

Study	Random sequence generation	Allocation concealment	Masking of participants	Masking of outcome assessors	Avoided incomplete or selective reporting	Free from other external sources of bias	Overall quality
Friedberg et al [34]	++a	++	–b	++	++	++	High
Chow et al [35]	++	++	–	++	++	++	High
Dale et al [36]	++	++	–	–	++	++	Moderate
Eyles et al [37]	++	++	–	–	++	++	Moderate
Barnason et al [38]	++	+c	–	–	++	++	Moderate
Choi et al [39]	++	+	–	–	++	–	Low
Engelen et al [40]	++	–	–	–	++	++	Moderate
Dorsch et al [41]	++	+	–	–	++	++	Moderate
Riches et al [42]	++	++	–	–	++	++	Moderate
Bae et al [43]	++	++	–	++	++	++	High
Peydró et al [44]	++	++	–	++	++	–	Moderate
Michelsen et al [45]	++	++	–	–	++	++	Moderate
Nagatomi et al [46]	++	+	–	–	++	++	Moderate

^aLow risk of bias.

^bHigh risk of bias.

^cModerate risk of bias.