Table 2.

Quality assessment of trials by modified Jadad scale*

Author	Randomization	Allocation concealment	Blinding	Withdrawals and dropouts	Score	Quality
Lilenbaum et al. 14	1	0	0	1	2	low
Zhou et al. 15	2	0	0	1	3	low
Xiong et al. 16	2	0	0	0	2	low
Koch et al. 17	2	2	2	1	7	high
Groen et al. 18	2	0	0	1	3	low
Liu and Huang 19	2	0	0	0	2	low

^*There are four items in the Jadad scale: randomizations; allocation concealment; double blinding; withdrawals and dropouts. If the item was not described in the study, the score would be 0; otherwise it was 1. If the method of the item was described and it was appropriate, the score would be 2; if the item of “withdrawals and dropouts” was not described, the score would be 0; if the item of “withdrawals and dropouts” was described and it was appropriate, the score would be 1. Randomized controlled trials were considered to be of high quality if the score was 4–7, and of low quality if the score was 1–3.