Table 3.
Summary of study quality according to the Cochrane Risk of Bias Tool, with (+) low risk of bias, (?) unclear risk of bias, (−) high risk of bias.
| Author, year | Random sequence generation | Allocation concealment | Blinding of participants and personnel | Blinding of outcome assessment | Incomplete outcome data | Selective reporting | Other bias |
|---|---|---|---|---|---|---|---|
| Bezalel et al., 2010 [27] | ? | − | − | + | ? | ? | − |
| Brosseau et al., 2012 part 1 [18] | + | − | − | + | ? | + | + |
| Brosseau et al., 2012 part 2 [19] | + | − | − | + | ? | + | ? |
| Coleman et al., 2012 [20] | ? | − | − | + | ? | ? | + |
| Ettinger et al., 2006 [28] | + | − | − | + | + | + | ? |
| Farr et al., 2010 [29] | + | − | − | − | + | + | − |
| Hurley et al., 2007 [15] | + | ? | − | + | ? | + | ? |
| Hurley et al., 2012 [30] | + | ? | − | + | + | + | + |
| Jessep et al., 2009 [21] | ? | ? | − | + | + | + | ? |
| Kovar et al., 1992 [31] | ? | − | − | − | + | + | ? |
| Sullivan et al., 1998 [16] | ? | − | − | − | + | ? | − |
| Mazzuca et al., 1997 [32] | − | − | − | ? | + | + | ? |
| McKnight et al., 2010 [33] | + | − | − | − | + | + | ? |
| Nunez et al., 2006 [34] | ? | − | − | − | + | + | ? |
| Ravaud et al., 2009 [22] | + | + | ? | − | + | + | + |
| Thomas et al., 2002 [35] | ? | − | − | + | − | ? | ? |
| Thomee et al., 2010 [23] | ? | − | − | − | ? | + | − |
| Victor et al., 2005 [24] | ? | − | − | + | −− | ? | ? |
| Wetzels et al., 2008 [25] | + | − | ? | + | ? | + | + |
| Yip et al., 2007 [17] | ? | − | − | − | ? | + | ? |
| Yip et al., 2008 [36] | ? | − | − | − | ? | + | ? |