Table 2.

Quality assessment of the included studies.

Trials	Randomization	Concealment allocation	Blinding of participants	Blinding of outcome assessors	Incomplete outcome data	Selective reporting	Other sources of bias
Chen et al. [13]	Unclear	Unclear	Unclear	Unclear	Low risk	High riskc	Unclear
Chen and Li [14]	Unclear	Unclear	Unclear	Unclear	Low risk	Low risk	Unclear
Chen et al. [15]	Unclear	Unclear	Unclear	Unclear	Low risk	Low risk	Unclear
Du [16]	Unclear	Unclear	Unclear	Unclear	Low risk	Low risk	Unclear
Li et al. [17]	Unclear	Unclear	Unclear	Unclear	Low risk	Low risk	Unclear
Liu et al. [18]	Unclear	Unclear	Unclear	Unclear	Low risk	Low risk	Unclear
Liu et al. [19]	Unclear	Unclear	Unclear	Unclear	Low risk	Low risk	Unclear
Liu et al. [20]	Unclear	Low risk	Low risk	Low risk	Low risk	Low risk	Unclear
Liu et al. [21]	High riska	Unclear	Unclear	Unclear	Low risk	Low risk	Unclear
Pang [22]	Low riskb	Unclear	Unclear	Unclear	Low risk	Low risk	Unclear
Qi and Zhang [23]	Unclear	Unclear	Unclear	Unclear	Low risk	Low risk	Unclear
Qin et al. [24]	High riska	Unclear	Unclear	Unclear	Low risk	Low risk	Unclear
Shao [25]	Low riskb	Unclear	Unclear	Unclear	Low risk	Low risk	Unclear
Shi et al. [26]	Unclear	Low risk	Low risk	Low risk	Low risk	Low risk	Unclear
Sun et al. [27]	Unclear	Low risk	Low risk	Low risk	Low risk	Low risk	Unclear
Tu [28]	Low riskb	Unclear	Unclear	Unclear	Low risk	Low risk	Unclear
Wu et al. [29]	High riska	Unclear	Unclear	Unclear	Low risk	High riskc	Unclear
Yang et al. [30]	Unclear	Unclear	Unclear	Unclear	Low risk	Low risk	Unclear
Zhang et al. [31]	Unclear	Unclear	Unclear	Unclear	Low risk	Low risk	Unclear
Niu et al. [32]	High riska	Unclear	Unclear	Unclear	Low risk	Low risk	Unclear

^aSequence generated by the date of admission or the condition of patients.

^bReferring to a random number table.

^cOne or more outcomes of interest in the review are reported incompletely so that they cannot be entered in a meta-analysis.