Table 3.
Risk of bias
| Lead author (year) | Country of conduct and year | Adequate sequence generation | Allocation concealment | Blinding outcome assessors | Blinding patients and providers | Incomplete outcome data addressed | Free of selective reporting | Funding source |
|---|---|---|---|---|---|---|---|---|
| Leibovitz (1971) [24] |
USA, 1970 |
High |
Unclear |
Unclear |
Unclear |
Low |
Unclear |
Low |
| Beutner (1979) [25] |
USA, 1974 |
Unclear |
Unclear |
Unclear |
Unclear |
Unclear |
Unclear |
Low |
| Rytel (1977) [26] |
USA, 1974 |
Low |
Low |
Unclear |
Unclear |
Low |
Unclear |
Unclear |
| Monto (1982) [27] |
USA, 1979 |
Unclear |
Unclear |
Unclear |
Unclear |
Low |
Unclear |
Low |
| Tannock (1984) [28] |
Australia, 1981 |
High |
Unclear |
Unclear |
Low |
Low |
Unclear |
Unclear |
| Keitel (1997) [29] |
USA, 1983 to 1988 |
Unclear |
Unclear |
Unclear |
Unclear |
Unclear |
Unclear |
Low |
| Gruber (1990) [30] |
USA, 1985 |
Unclear |
Unclear |
Unclear |
Low |
Unclear |
Unclear |
Low |
| Edwards (1994) [31] |
USA, 1986 to 1990 |
Low |
Low |
Unclear |
Low |
Unclear |
Unclear |
Low |
| Clover (1991) [32] |
USA, 1989 |
Unclear |
Unclear |
Unclear |
Unclear |
Unclear |
Unclear |
Low |
| Govaert (1994) [33] |
The Netherlands, 1991 |
Unclear |
Low |
Unclear |
Low |
Low |
Unclear |
Low |
| Powers (1995) [34] |
USA, 1993 |
Unclear |
Unclear |
Unclear |
Low |
Unclear |
Unclear |
Low |
| Belshe (1998) [35] |
USA, 1996 |
Unclear |
Unclear |
Unclear |
Low |
Unclear |
Unclear |
Low |
| Rudenko (2001) [36] |
Russia, 1996 |
Unclear |
Unclear |
Unclear |
Unclear |
Unclear |
Unclear |
Unclear |
| Belshe (2000) [37] |
USA, 1997 |
Unclear |
Unclear |
Unclear |
Low |
Unclear |
Unclear |
Low |
| Bridges (2000) [38] |
USA, 1997 to 1998 |
Unclear |
Unclear |
Unclear |
Low |
Low |
Unclear |
Low |
| Hoberman (2003) [39] |
USA, 1999 to 2000 |
Low |
Unclear |
Low |
High |
Low |
Unclear |
Unclear |
| Tam (2007) [40] |
Multisite trial in Asia, 2000 to 2001 |
Low |
Low |
Unclear |
Low |
Unclear |
Unclear |
Unclear |
| Vesikari (2006) [41] |
Multisite trial in Europe and Israel, 2000 to 2001 |
Unclear |
Unclear |
Unclear |
Low |
Low |
Unclear |
Unclear |
| Bracco Neto (2009)a[10] |
Multisite trial in South Africa and South America, 2001 to 2002 |
Low |
Low |
Low |
Unclear |
Unclear |
Unclear |
Unclear |
| Lum (2010) [43] |
Multisite trial in Asia, Europe and South America, 2002 |
Unclear |
Low |
Low |
Low |
Low |
Unclear |
Unclear |
| Forrest (2008) [42] |
Multisite in Asia, 2002 |
Unclear |
Unclear |
Unclear |
Low |
Unclear |
Unclear |
Unclear |
| Langley (2011) [44] |
Canada, 2003 |
Unclear |
Unclear |
Low |
Low |
Low |
Unclear |
Unclear |
| Ohmit (2006)a[11] |
USA, 2004 |
Unclear |
Unclear |
Unclear |
Low |
Low |
Low |
Low |
| Treanor (2007)a[12] |
USA, 2004 |
Unclear |
Unclear |
Unclear |
Low |
Low |
Low |
Unclear |
| Beran (2009) [45] |
Czech Republic, 2005 |
Low |
Low |
Unclear |
Low |
Low |
High |
Unclear |
| Jackson (2010) [15] |
USA, 2005 |
Low |
Low |
Unclear |
Unclear |
Low |
Low |
Unclear |
| Ohmit (2008)a[13] |
USA, 2005 |
Unclear |
Unclear |
Unclear |
Low |
Low |
Low |
Low |
| Beran (2009) [46] |
Multisite trial Europe, 2006 |
Unclear |
Unclear |
Unclear |
Low |
Low |
High |
Unclear |
| Monto (2009)a[14] |
USA, 2007 |
Unclear |
Unclear |
Unclear |
Low |
Low |
Low |
Unclear |
| Frey (2010) [47] |
Multisite trial North America and Europe, 2007 |
Unclear |
Unclear |
Unclear |
Unclear |
Low |
Low |
Unclear |
| Treanor (2011) [48] |
USA, 2007 |
Unclear |
Unclear |
Unclear |
Unclear |
Low |
Low |
Unclear |
| Barrett (2011) [49] |
Multisite trial in USA, 2008 |
Low |
Low |
Unclear |
Low |
Unclear |
Unclear |
Unclear |
| Cowling (2010) [50] |
Hong Kong, 2008 |
Low |
Low |
Unclear |
Low |
Low |
Low |
Low |
| Talaat (2010) [51] | USA, 2009 | Unclear | Unclear | Unclear | Low | Low | Unclear | Unclear |
aUnpublished data was obtained from the author(s).