Table 2.
Quality assessment of trails included.
| Study | Adequate sequence generation | Adequate allocation concealment | Blinding | Incomplete outcome data adequately addressed | Free of selective reporting | Free of other bias |
|---|---|---|---|---|---|---|
| Petrov 2006 | + | ? | − | + | + | ? |
| Eckerwall 2006 | + | + | − | + | + | + |
| Gupta 2003 | + | + | − | + | + | + |
| Louie 2005 | + | + | + | + | + | − |
| Olah 2002 | ? | ? | − | + | + | + |
| McClave 1997 | ? | ? | − | + | + | + |
| Kalfarentzos 1997 | + | + | − | + | + | + |
| Casas 2007 | + | + | − | + | + | ? |
| Abou-Assi 2002 | ? | ? | − | + | + | + |
| Qin 2008 | + | + | + | + | + | − |
| Sun 2013 | ? | ? | − | + | + | + |
| Zou 2014 | ? | ? | − | + | + | ? |
+ is “yes”, − is “no”, ? is “unclear”.