Table 2 Risk of bias assessed using the SIGN score
Study | SIGN score | SIGN comment |
|---|---|---|
Benes, 2010 [38] Europe | ++ | - |
Buettner, 2008 [11] Europe | - | Blinding and concealment not clear |
Forget, 2010 [37] Europe | ++ | - |
Goepfert, 2013 [36] Europe | ++ | - |
Harten, 2008 [35] Europe | - | Blinding not clear, outcomes not defined |
Kapoor, 2008 [39] India | - | Randomization and blinding not clear, outcomes not defined |
Lopes, 2007 [10] Brazil | ++ | - |
Mayer, 2010 [40] Europe | + | Randomization not clear |
Ramsingh, 2013 [34] USA | + | Intention-to-treat analysis not performed. |
Salzwedel, 2013 [30] Europe | ++ | Multicentric trial |
Sheeren, 2013 [33] Europe | + | Intention-to-treat analysis not performed, multicentric trial |
Zhang Ju, 2012 [32] China | + | Intention-to-treat analysis not performed |
Zhang Ji, 2013 [31] China | - | Randomization and blinding not clear, outcomes not defined |
Zheng, 2013 [29] China | ++ | - |