Table 6. Quality of included studies.
| Study | Was the allocation sequence adequately generated? | Was the allocation adequately concealed? | Were baseline outcome measurements similar? | Were baseline characteristics similar? | Were incomplete outcome data adequately addressed? | Was knowledge of the allocated interventions adequately prevented during the study? | Was the study adequately protected against contamination? | Was the study free from selective outcome reporting? | Was the study free from other risks of bias? | Criteria met |
|---|---|---|---|---|---|---|---|---|---|---|
| Beland 2006a [57]; Beland 2006b [58] | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | 9 |
| Bernabei 1998 [59] | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | 9 |
| Bird 2010 [60] | No | No | No | No | Yes | Yes | Yes | Yes | No | 4 |
| Boult 2008 [61]; Leff 2009 [62]; Boyd 2010 [63]; Boult 2011 [64]; Boult 2013 [65] | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | 9 |
| Boyd 1996 [66] | No | Unclear | Yes | Yes | Unclear | Yes | Unclear | Yes | Unclear | 4 |
| Burns 1995 [67]; Burns 2000 [68] | Yes | Yes | Yes | Yes | Unclear | Yes | Yes | Yes | Yes | 8 |
| Coburn 2012 [69] | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | 9 |
| Counsell 2007 [70]; Counsell 2009 [71] | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | 9 |
| Dalby 2000 [72] | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Unclear | Yes | 8 |
| De Stampa 2014 [73] | No | No | Yes | Yes | Yes | Yes | Yes | Yes | Yes | 7 |
| Dorr 2008 [74] | No | Yes | Yes | Yes | Yes | Yes | Yes | Yes | No | 7 |
| Enguidanos 2006 [75] | Unclear | Unclear | Yes | Yes | Unclear | Unclear | Unclear | Unclear | Yes | 3 |
| Fan 2012 [76] | Yes | Yes | Yes | Yes | Yes | Yes | Unclear | Yes | Yes | 8 |
| Fitzgerald 1994 [77] | Unclear | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | 8 |
| Fordyce 1997 [78] | Unclear | Unclear | No | No | Yes | Yes | Unclear | Yes | Yes | 4 |
| Gagnon 1999 [79] | Yes | Yes | Yes | Yes | Yes | Yes | No | Yes | Yes | 8 |
| Gravelle 2007 [80] | No | No | Yes | No | Unclear | Yes | Yes | Yes | Yes | 5 |
| Hogg 2009 [81]; Gray 2010 [82] | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | 9 |
| Kruse 2010 [83] | No | Yes | Unclear | No | Yes | Yes | Yes | Yes | Yes | 6 |
| Leung 2004 [84] | Unclear | Unclear | No | Yes | Unclear | Yes | Unclear | Yes | Yes | 4 |
| Levine 2012 [85] | Yes | Unclear | Unclear | Yes | Yes | Yes | Unclear | Yes | Yes | 6 |
| Martin 2004 [86] | Unclear | Unclear | Unclear | No | Unclear | Yes | Unclear | Yes | Yes | 3 |
| Metzelthin 2013[87] | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | 9 |
| Morishita 1998 [88]; Boult 2001 [89] | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Unclear | 8 |
| Newcomer 2004 [90] | Unclear | Unclear | Yes | Yes | Yes | Yes | Unclear | Yes | Yes | 6 |
| Ploeg 2010 [91] | Yes | Yes | Unclear | Yes | Yes | Yes | Yes | Yes | Yes | 8 |
| Rodenas 2008 [92] | Yes | Yes | No | No | Yes | Yes | Unclear | Yes | Yes | 6 |
| Rubenstein 2007 [93] | Yes | Yes | Yes | Unclear | No | Yes | Yes | Yes | Yes | 7 |
| Schraeder 2001 [94] | Unclear | Yes | No | No | Yes | Yes | Yes | Yes | Yes | 6 |
| Schraeder 2008 [95] | No | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | 8 |
| Shannon 2006 [96]; Alkema 2007 [97] | Unclear | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | 8 |
| Sledge 2006 [98] | Yes | Yes | Unclear | Yes | Yes | Yes | Yes | Yes | Yes | 8 |
| Stuck 2000 [99] | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | 9 |
| Sylvia 2008 [100]; Boyd 2008 [101] | No | Yes | Yes | Yes | Yes | Yes | Unclear | Yes | Yes | 7 |
| Toseland 1996 [102]; Toseland 1997 [103]; Engelhardt 1996 [104]; Engelhardt 2006 [105] | Unclear | Unclear | Unclear | Yes | Yes | Yes | Unclear | Yes | Yes | 5 |
| van Hout 2010 [106] | Yes | Yes | Unclear | Yes | Yes | Yes | Yes | Yes | Yes | 8 |