Table 4 Risk of bias of included trials
Source of bias | |||||
|---|---|---|---|---|---|
First author | Allocation concealment | Selective recruitment | Incomplete outcome data | Survival selection | Summary risk of bias |
Naschitz 1988 [27] | yes | yes | no | yes | high |
Walsh (1991) [21] | yes | yes | no | no | moderate |
Fowkes (1993) [25] | yes | yes | no | yes | high |
Whyman (1993) [30] | No | No | yes | No | low |
Bird (1999) [26] | yes | yes | yes | yes | High |
Smith (1998) [29] | No | yes | yes | yes | high |
Smith (2003) [28] | No | yes | yes | yes | high |
Aquino (2005) [24] | no | yes | no | yes | moderate |