Table 2.
Risk of bias assessment (+ low risk of bias; − high risk of bias;? unclear risk of bias).
| Study | Selection bias |
Performance and detection bias |
Attrition bias |
Reporting bias |
Other sources of bias |
|||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Random sequence generationa | Allocation con-cealmentb | Blinding: Participantsc | Blinding: Personneld | Blinding: Outcome assessmente | Dropoutf | ITTg | Selective reportingh | Co-interventionsi | Similar Groupsj | Compliancek | Timingl | |
| Bauer et al. (2012)m | + | + | – | – | ? | + | + | + | + | + | ? | + |
| Zwerenz et al. (2017a) | + | + | − | − | − | − | + | + | + | + | − | ? |
| Bischoff et al. (2013) | ? | ? | – | – | − | − | − | + | + | + | + | + |
| Ebert et al. (2013) | + | + | – | − | − | − | + | + | + | + | + | + |
| Fichter et al. (2012)n | ? | + | – | − | + | + | − | + | + | + | + | + |
| Gulec et al. (2014) | ? | ? | – | − | − | − | − | + | + | ? | – | + |
| Holländare et al. (2011)o | + | + | – | − | ? | + | + | + | − | ? | + | + |
| Jacobi et al. (2017) | + | + | − | − | + | − | + | + | + | + | + | + |
| Kordy et al. (2016) | + | + | − | − | + | + | + | + | + | ? | + | ? |
| Kraft et al. (2017) | + | + | − | − | − | + | − | + | − | − | − | + |
| Norlund et al. (2018) | + | ? | − | − | − | + | + | + | − | ? | − | + |
| Schmädeke and Bischoff (2015) | − | − | − | − | − | − | − | + | − | − | + | + |
| Välimäki et al. (2017) | + | + | − | − | + | –p | + | + | + | ? | ? | + |
| Willems et al. (2017a)q | + | + | − | ? | − | + | +r, s | + | − | + | – | + |
| Zwerenz et al. (2017a) | + | + | − | − | − | − | +s | + | − | + | + | + |
| Zwerenz et al. (2017c) | + | + | − | − | − | − | + | + | + | ? | − | + |
Adequate generation of a randomized sequence.
Participants and investigators could not foresee assignment.
Intervention and control group are indistinguishable for the participants.
Intervention and control group are indistinguishable for the care providers.
Intervention and control group are indistinguishable for the outcome assessors for primary outcome (for patient-reported outcomes, it is adequate if patients are blinded).
Dropout must be described and reasons must be given. Dropout should not exceed 20% for short-term follow-up (3–6 months), 30% for medium-term follow-up (6–12 months), 35% for long term follow-up (>12 months) in guided and 40% in unguided interventions.
ITT: intention-to-treat analyses. All randomized patients are reported and analyzed in the group they were allocated to by randomization.
Results of all pre-specified outcomes have to be adequately and completely reported.
Cointerventions must be specified.
Groups should not differ significantly at baseline regarding outcomes and main demographics.
Acceptable compliance with the main component(s) of the intervention (e.g. intensity, duration, frequency).
Identical timing of outcome assessments for intervention and control groups.
Additional publications: Bauer et al. (2011a),Bauer et al. (2013).
Additional publication: Fichter et al. (2013).
Additional publication: Holländare et al. (2013).
Drop-out rates from patient survey.
Additional publication: Willems et al. (2017b).
Additional ITT Data provided by study author.
ITT-analyses provided, but baseline-measurement after allocation.