Table 2. Quality assessment of the included RCTs.

	Kuntz et al.	Naspro et al.	Zhang et al.	Geavlete et al.	Rao et al.	Chen et al.	Ou et al.
Was the study described as randomized?	1	1	1	1	1	1	1
Was the method of randomization described and appropriate?	1	1	0	1	1	1	1
Was the study described as double blind?	0	0	0	0	0	0	0
Was the method of blinding described and appropriate?	0	0	0	0	0	0	0
Was there a description of withdrawals and dropouts?	1	1	1	1	1	1	1
Total	3	3	2	3	3	3	3