Table 1 Quality assessment of included studies
Study | Random sequence generation (selection bias) | Allocation concealment (selection bias) | Blinding of participants and personnel (performance bias) | Binding of outcome assessment (detection bias) | Incomplete outcome data (attention bias) | Selective reporting (reporting bias) |
|---|---|---|---|---|---|---|
Chen et al. 2004 [7] | L | L | U | U | L | L |
Chullikana et al. 2015 [10] | L | L | L | L | L | L |
Gao et al. 2013 [28] | L | L | L | H | L | L |
Gao et al. 2015 [27] | L | L | L | L | L | L |
Hare et al .2009 [29] | L | L | L | L | U | L |
Houtgraaf et al. 2012 [12] | L | L | L | L | L | L |
Lee et al. 2014 [30] | L | H | H | H | L | L |
Wang et al. 2014 [31] | L | L | U | U | L | L |