Table 2.

Risk of bias of included RCTs.

Study	Random sequence generation	Allocation concealment	Blinding of participants	Blinding of personnel	Blinding of outcome assessment	Incomplete outcome data	Selective reporting	Other sources of bias
Xiao et al. (2020)	Unclear	Unclear	Unclear	Unclear	Unclear	Low	Low	Low
Fu et al. (2020a)	Low	Unclear	Unclear	Unclear	Unclear	Low	Low	Low
Fu et al.(2020b)	Unclear	Unclear	Unclear	Unclear	Unclear	Low	Low	Low
Duan et al. (2020)	High	Unclear	Unclear	Unclear	Unclear	Low	Low	Low
Wang et al. (2020)	Unclear	Unclear	Unclear	Unclear	Unclear	Unclear	Low	Low
Ding et al. (2020)	Low	Unclear	Unclear	Unclear	Unclear	Low	Low	Low