Table 7 Summary of risk of bias (high, low or unclear) in the 11 included quantitative studies
Study | Sequence generation | Treatment allocation concealment | Performance bias (participant blind) | Detection bias (outcome assessment blind) | Baseline comparability | Groups treated equally | Selective outcome reporting | Incomplete outcome data | Researcher allegiance |
|---|---|---|---|---|---|---|---|---|---|
Beebe 2010 [29] | Unclear | Unclear | High | Low | Unclear | High | Low | Unclear | Low |
Broome 2001 [13] | Unclear | Unclear | High | Unclear | Unclear | Low | Low | Unclear | Low |
Gussak 2007 [30] | Unclear | Unclear | High | Unclear | High | High | Low | Unclear | High |
Hattori 2011 [24] | Unclear | Unclear | High | Unclear | Low | Low | Low | Low | Low |
Kim 2013 [15] | Unclear | Unclear | High | High | Low | Low | Low | Low | High |
Lyshak-Stelzer 2007 [18] | Unclear | Unclear | High | Unclear | Low | Low | Low | High | Low |
McCaffrey 2011 [19] | Low | Unclear | High | Unclear | Low | Low | Low | Low | High |
Monti 2006 [16] | Unclear | Unclear | High | Unclear | High | High | Low | Low | Low |
Monti 2012 [17] | Unclear | Unclear | High | Unclear | Low | Low | Low | High | Low |
Rusted 2006 [20] | Unclear | Unclear | High | Unclear | High | Low | Low | High | Low |
Thyme 2007 [14] | Low | Low | High | Unclear | Unclear | Low | Low | Low | Low |