Table 2.
Quality of methods in the studies included in review
| Study details (country, design, funding) | Inclusion & exclusion criteria |
Outcome |
Sequence generation | Allocation concealment | Blinding | Sample size | Attrition % | Funding | |
|---|---|---|---|---|---|---|---|---|---|
| 1ry | 2ry | ||||||||
| ZA 2 |
✓ |
✓ |
✓ |
A |
A |
NP‡ |
✓║ |
≥20# |
G |
| Fairall, 2012 [36] (Cohort 2) | |||||||||
| ZA 1 |
✓† |
✓ |
✓ |
A |
A |
NP‡ |
✓║ |
≥20# |
G |
| Fairall, 2012 [36] (Cohort 1) | |||||||||
| NL 6 |
✓† |
✓ |
✓ |
I |
A |
NP |
✓ |
<20 |
G |
| Houweling, 2011 [30] | |||||||||
| NL 5 |
✓† |
✓ |
|
A |
A |
NP |
✓¶ |
<20 |
NR |
| Kuethe, 2011 [25] | |||||||||
| RU 1 |
✓ |
|
|
U |
I |
‡ |
✓¶ |
≥20 |
None |
| Andryukhin, 2010 [46] | |||||||||
| NL 4 |
✓ |
✓ |
|
A |
U |
I‡,§ |
✓ |
<20 |
P/Ind. |
| Voogdt-Pruis, 2010 [16] | |||||||||
| NL 3 |
✓† |
|
|
A |
A |
NP |
NP |
≥20 |
G |
| Dierick-Van Dale, 2009 [39] | |||||||||
| UK 9 |
✓† |
|
|
A |
A |
NP§ |
✓ |
<20# |
NR |
| Chan, 2009 [42] | |||||||||
| NL 2 |
✓† |
✓ |
✓ |
U |
U |
NP |
✓║ |
≥20 |
NR |
| Du Moulin, 2007 [37] | |||||||||
| USA 6 |
* |
|
|
U |
U |
NP |
NP |
<20 |
G |
| Hiss, 2007 [32] | |||||||||
| NL 1 |
* |
✓ |
✓ |
U |
U |
NP§ |
✓║ |
≥20 |
NR |
| Hesselink, 2004 [33] | |||||||||
| UK 8 |
* |
✓ |
✓ |
I |
I |
NP |
✓¶ |
<20# |
NR |
| Denver, 2003 [40] | |||||||||
| UK 7 |
✓ |
✓ |
✓ |
A |
A |
NP |
✓ |
<20 |
P/Ind. |
| Jarman, 2002 [29] | |||||||||
| UK 6 |
*† |
✓ |
✓ |
A |
U |
U |
✓ |
≥20# |
NR |
| Kernick, 2002 [27] | |||||||||
| US 5 |
* |
|
|
U |
U |
NP |
✓¶ |
≥20 |
G |
| Mundinger, 2000 [22,24] | |||||||||
| UK 5 |
✓ |
✓ |
|
A |
U |
U |
✓¶ |
≥20 |
Ind. |
| Kernick, 2000 [28] | |||||||||
| UK 4 |
✓ |
✓ |
✓ |
A |
A |
NP |
✓║,¶ |
≥20 |
G |
| Kinnersley, 2000 [26] | |||||||||
| UK 3 |
✓ |
|
|
A |
A |
NP |
NR║,¶ |
≥20 |
P |
| Venning, 2000 [17] | |||||||||
| UK 2 |
✓ |
|
|
A |
A |
NP |
✓¶ |
≥20 |
G |
| Shum, 2000 [18] | |||||||||
| US 4 |
✓ |
|
|
I |
I |
NP |
NP |
U |
NR |
| Hemani, 1999 [34] | |||||||||
| UK 1 |
✓ |
|
|
A |
I |
NP§ |
✓ |
≥20# |
G |
| Campbell, 1998 [19-21,41,43-45] | |||||||||
| US 3 |
✓ |
✓ |
|
U |
U |
A‡ |
NR |
U |
NR |
| Winter, 1981 [15] | |||||||||
| US 2 |
* |
|
|
U |
U |
NP |
NR |
<20 |
NR |
| Flynn, 1974 [35] | |||||||||
| US 1 |
* | U | U | NP§ | NR | U# | G | ||
| Lewis, 1967 [23] | |||||||||
Legend.
Studies are listed by year (y) of publication, in decreasing order. Blinding: whether patients, care providers and outcome assessors were blinded. Attrition of more than 20% is of significant concern. Intention to treat (ITT) whether study authors analysed all patients based on their original group allocation regardless of protocol violations or non-compliance. US, United States; NL, The Netherlands; UK, United Kingdom; ZA, South Africa; RU, Russia; I, Inadequate; A: Adequate; U, Unclear; NP, Not Performed; NR, Not reported; Funding, Government (G), Industry (Ind.) or Private (P) grant.
*Only the inclusion criteria was reported.
†Not all factors tested at baseline were comparable between groups.
‡Fairall et al. (2012) [36] partly blinded data analysts; Andryukhin et al. (2010) [46] blinded clinicians not patients; Voogdt-Pruis et al. (2010) [16] blinded patients not clinicians; Winter (1981) [15] blinded patients and clinicians.
§Outcome assessors blinded for some or all outcomes.
║Used a cluster effect approach (e.g. Huber-White).
¶Reached the least target sample required to achieve power.
#Used ITT strategies to deal with missing data.