Table 4. Methodological components.
| Study | Random sequence adequately generated? | Allocation concealed? | Participants and RTW-coordinators blinded? | RTW-outcome assessor blinded? | PRO- outcome assessor blinded? | Loss to follow-up of RTW-outcomes [%] | Loss to follow-up of PROs [%] | Intention to treat analysis1 | Selective reporting2 | Other |
| Bültmann 2009 | Y | Y3 | N | Y | N | 5 | 34 | Y | ? | |
| Davey 1994 | Y | Y | N | N | N | 0 | 0 | Y | ? | |
| Donceel 1999 | Y | Y | N4 | N | n.a. | 0 | n.a. | (Y) | ? | 9 |
| Feuerstein 2003 | Y | N3 | N | (N) | N | 403 | 36–61 | (N) | Y5,8 | |
| Lambeek 2010 | Y | Y | N | N | N | 7 | 13 | Y | N | |
| Lindh 1998 | (N) | (N) | N | Y | n.a. | ? | n.a. | Y | Y6,8 | |
| Purdon 2006 | Y | Y3 | N | N | N | 28 | 29 | Y | ? | |
| Rossignol 2000 | Y | Y | N | Y | N | 0 | 18 | Y | ? | |
| V. d. Feltz-Cornelis 2010 | Y | Y | N | Y | N | 18 | 27 | Y | Y7,8 | 9 |
RTW = return to work, PRO = patient reported outcomes, Y = yes, (Y) = probably Yes, N = No, (N) = probably no, ? = unclear, n.a. = not applicable.
Participants analysed in the group to which they were initially assigned.
“No” if protocol published and all outcomes correctly reported; “?” if no protocol published and selective reporting not obvious.
From personal correspondence.
Participants were probably not aware of the intervention.
RTW-outcomes not published, incomplete outcome information (see table 3).
Results presented in subgroups, incomplete outcome information (see table 3).
Primary outcome not mentioned in protocol.
Incomplete outcome information (see table 3).
Cluster randomised trials: No risk of recruitment bias. Baseline information of individual clusters not reported. Effects of RTW-outcomes not corrected for possible design effects (risk of inflated precision).