Effects of simvastatin on serum adiponectin: a meta-analysis of randomized controlled trials

Table 2 Summary of study quality evaluated by Cochrane risk of biases tool

Author (year)	Sequence generation	Allocation concealment	Blinding of participants and personnel	Blinding of outcome assessment	Incomplete outcome data	Selective outcome reporting	Other potential threats	Total
Koh 2004 [13]	Unclear	Unclear	Yes	Yes	Yes	Unclear	Unclear	3
Koh 2005a [14]	Unclear	Unclear	Yes	Yes	Yes	Unclear	Unclear	3
Devaraj 2007 [15]	Unclear	Unclear	Yes	Yes	Yes	Unclear	Unclear	3
Pfutzner 2007 [16]	Unclear	Unclear	No	No	Yes	Unclear	Unclear	1
Gouni-Berthold 2008 [17]	Unclear	Unclear	Unclear	Unclear	Yes	Unclear	Unclear	1
Koh 2008–10 mg^a [18]	Unclear	Unclear	Yes	Yes	Yes	Unclear	Unclear	3
Koh 2008–20 mg^a [18]	Unclear	Unclear	Yes	Yes	Yes	Unclear	Unclear	3
Koh 2008–40 mg^a [18]	Unclear	Unclear	Yes	Yes	Yes	Unclear	Unclear	3
Koh 2008–80 mg^a [18]	Unclear	Unclear	Yes	Yes	Yes	Unclear	Unclear	3
Koh 2009 [20]	Unclear	Unclear	Yes	Yes	Yes	Unclear	Unclear	3
Hu 2009 [19]	Unclear	Unclear	Yes	Yes	Yes	Unclear	Unclear	3
Koh 2011b-20 mg^b [21]	Unclear	Unclear	No	No	Yes	Unclear	Unclear	1
Koh 2011b-40 mg^b [21]	Unclear	Unclear	No	No	Yes	Unclear	Unclear	1
Moezzi 2014 [23]	Unclear	Unclear	Yes	Yes	Yes	Unclear	Unclear	3
Krysiak 2014 [22]	Unclear	Unclear	No	No	Yes	Unclear	Unclear	1
Koh 2015 [24]	Unclear	Unclear	Yes	No	Yes	Unclear	Unclear	2

Yes, low risk of bias; Unclear, uncertain risk of bias; No, high risk of bias
^aThe study by Koh et al (2008) [18] included four simvastatin treatment arms with dosages of 10, 20, 40, 80 mg/d respectively, and these comparisons were included separately
^bThe study by Koh et al (2011b) [21] included two simvastatin treatment arms with dosages of 20 and 40 mg/d respectively, and both the comparisons were included separately

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