Table 3 Risk of bias and methodologic quality assessment of included studies
Study | Rating based on Cochrane risk-of-bias tool | Downs and Black checklist | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Internal validity | |||||||||||||
Sequence generation | Allocation concealment | Blinding | Incomplete outcome data | Selective outcome reporting | Other bias | Summary | Reporting | External validity | Bias | Confounding | Power | Total | |
/11 | /3 | /7 | /6 | /5 | /32 | ||||||||
RCTs or subgroup of RCTs | |||||||||||||
McIntyre et al. 2006a | Low | Low | High | Low | Low | Low | Low | 10 | 3 | 6 | 5 | 0 | 24 |
Lacroix et al. 2007a | Low | Low | High | Low | Low | Low | Low | 11 | 3 | 5 | 6 | 0 | 25 |
Naidech et al. 2010 | Low | Low | Unclear | Low | Low | Low | Low | 7 | 1 | 6 | 5 | 2 | 21 |
Nonrandomized studies | |||||||||||||
Flückiger et al. 2010 | 5 | 3 | 6 | 4 | 0 | 18 | |||||||
George et al. 2008 | 9 | 2 | 4 | 3 | 0 | 18 | |||||||
Warner et al. 2010 | 9 | 2 | 6 | 3 | 1 | 21 | |||||||