Table 2.

Assessment of literature quality

Literature resources	Randomization	Random sequence generation	Allocation concealment	Blinding methodology	Withdrawal and dropouts	Jadad score
Liet et al. 2006 [14]	Yes	Computer-generated	Yes	Yes	6/0	5
Standl et al. 2008 [15]	Yes	Sealed randomization envelopes	Yes	None	13/1	4
Akech et al. 2010 [16]	Yes	Randomization cards	Yes	Unclear	16/0	4
Van Der Linden et al. 2013 [17]	Yes	By means of a macro written in SAS®, version 9.3.1.	Yes	Double-blinded	0/0	5
Liet et al. 2003 [18]	Yes	Unclear	Unclear	Double-blinded	Unclear	2
Hanart et al. 2009 [19]	Yes	The randomization assignment was concealed in an envelope	Yes	Double-blinded	Unclear	4
Akkucuk et al. 2013 [20]	Yes	Unclear	Unclear	Unclear	Unclear	1
Chong Sung et al. 2006 [21]	Yes	Unclear	Unclear	Unclear	Unclear	1
Haas et al. 2007 [22]	Yes	Unclear	Unclear	Unclear	Unclear	1
Wills et al. 2005 [23]	Yes	Computer-generated	Yes	Yes	0/1	5
Sahoo et al. 2007 [24]	Yes	Unclear	Unclear	Unclear	0/7	2
Osthaus et al. 2009 [25]	Yes	Computer-generated	Unclear	None	Unclear	2
Witt et al. 2008 [26]	Yes	Unclear	Unclear	None	Unclear	1