Table 1.

Quality assessment of all the 16 randomized controlled trials found in literature and included in this study

Ref.	Randomization	Allocation concealment	Blind	Withdrawal and dropout	Jadad score	ITT
Yonemura et al[29], 1993	Adequate	Inadequate	Adequate	Well reported	5	NR
Shchepotin et al[30], 1995	Unclear	Unclear	Inadequate	NR	1	NR
Kang et al[31], 1996	Unclear	Unclear	Inadequate	Well reported	3	NR
Lygidakis et al[32], 1999	Inadequate	Unclear	Inadequate	Well reported	2	NR
Takiguchi et al[33], 2000	Unclear	Inadequate	inadequate	Well reported	2	NR
Wang et al[22], 2000	Unclear	Unclear	Inadequate	Well reported	3	NR
Kobayashi et al[35], 2000	Adequate	Adequate	Inadequate	Well reported	5	NR
Hartgrink et al[4], 2004	Adequate	Adequate	Inadequate	Well reported	5	NR
Nio et al[36], 2004	Inadequate	Inadequate	Inadequate	Well reported	1	NR
Zhao et al[37], 2006	unclear	Unclear	Inadequate	Well reported	3	NR
Cunningham et al[17], 2006	Adequate	Adequate	Adequate	Well reported	7	YES
Schuhmacher et al[15], 2010	Unclear	Unclear	Unclear	Well reported	4	YES
Imano et al[38], 2010	unclear	unclear	Unclear	Well reported	4	NR
Biffi et al[39], 2010	Unclear	Unclear	Unclear	Well reported	4	YES
Qu et al[40], 2010	Adequate	Unclear	Unclear	NR	4	NR
Ychou et al[18], 2011	Adequate	Well reported	Unclear	Well reported	6	YES

NR: Not reported; ITT: Intention-to-treat analysis.