Table 2.

The quality of the nine studies.

Study year	Research method	Randomization	Blinding	Allocation concealment	Withdrawal and loss	Intention to treat analysis	Baseline demographic characteristics	Jadad score	Quality
Fishbane et al. [4], 2009	Prospective, randomized, placebo-controlled, double-blinded trial	Computer generated	Double- blinded	Adequate	Description	Used	Similar	5	A
Alborzi et al.[5], 2008	A randomized, double-blinded pilot trial	Computer generated	Double- blinded	Adequate	Description	Used	Similar	5	A
Agarwal et al.[6], 2005	Three, randomized, placebo-controlled, double-blinded trials	—	Double- blinded	Unclear	—	Unclear	Similar	2	B
Martin et al.[7], 1998	Randomized, placebo-controlled, double-blinded multi-investigator study	—	Double- blinded	Unclear	No	—	Similar	3	B
Abboud et al.[8], 2006	Three, prospective, randomized, placebo-controlled, double-blinded multicenter studies	—	Double- blinded	Unclear	—	Unclear	Similar	2	B
Coyne et al.[9], 2006	Three, randomized, placebo-controlled trials	Computer generated	Double- blinded	Adequate	—	Unclear	Similar	4	B
Greenbaum et al.[10], 2007	Randomized, placebo-controlled, double-blinded trial	—	Double- blinded	Unclear	Description	Unclear	Similar	3	B
Ross et al.[11], 2007	Randomized, placebo-controlled, double-blinded trial	Computer generated	Double- blinded	Adequate	—	Unclear	Similar	3	B
De Zeeuw et al. [12], 2010	A multicenter randomized placebo-controlled, double-blinded clinical trial	Computer generated	Double- blinded	Adequate	Description	Used	Similar	5	A