Table 1

Risk of bias assessment using the criteria from the Cochrane Back Review Group

 Study Item 1. Was the method of randomisation adequate? 2. Was the treatment allocation concealed? 3. Was the patient blinded to the intervention? 4. Was the care provider blinded to the intervention? 5. Was the outcome assessor blinded to the intervention? 6. Was the drop-out rate described and acceptable? 7. Were all randomised participants analysed in the group to which they were allocated? 8. Are reports of the study free of suggestion of selective outcome reporting? 9. Were the groups similar at baseline regarding the most important prognostic indicators? 10. Were cointerventions avoided or similar? 11. Was the compliance acceptable in all groups? 12. Was the timing of the outcome assessment similar in all groups? 13. Are other sources of potential bias unlikely? Score (0/13) Aboagye et al 39 Unclear Unclear No No No No Yes Yes No Unclear Unclear Yes Yes 4 Bello et al 40 Yes Yes Unclear No Unclear No Yes Unclear Yes Unclear No Yes Yes 6 Bosmans et al 34 Yes Yes No No No Yes Yes No Yes Yes No Yes Yes 8 Carr et al 41 Yes Unclear No No No No Yes Unclear Yes Unclear No Yes Yes 5 Cherkin et al 42 Yes Unclear No No No Yes Yes Unclear Yes Yes Yes Yes Yes 8 Chuang et al 43 Yes Yes No No No Yes Yes Yes Yes Yes No Yes Yes 9 Critchley et al 44 Yes Yes No No No No Yes Yes Yes Yes Unclear Yes Yes 8 van Dongen et al 38 Yes Yes No No No No Yes No Yes Yes Unclear Yes Yes 7 Henchoz et al 45 Yes Yes No No No No Yes Yes Yes Yes No Yes Yes 8 Hlobil et al 46 Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes 10 Hollinghurst et al 47 Yes Yes No No No No Yes Yes Yes Unclear Yes Yes Yes 8 Hurley et al 48 Yes Yes No No No Yes Yes Yes Yes Yes No Yes Yes 9 Korthals-de Bos et al 35 Yes Yes No No No Yes Yes Yes Yes No Yes Yes Yes 9 Leininger et al 36 Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes 10 Manca et al 55 Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes 10 van der Roer et al 53 Yes Yes No No No Yes Yes No Yes Yes No Yes Yes 8 Rosenfeld et al 37 Yes Unclear No No No Yes Yes Yes Yes No Yes Yes Yes 8 Seferlis et al 49 Unclear Unclear No No No No Yes Yes Unclear Unclear Yes Yes Yes 5 Smeets et al 50 Yes Yes No No No Yes Yes Yes Yes Yes No Yes Unclear 8 Torstensen et al 52 Unclear Unclear No No No Yes Yes Unclear Yes Unclear Unclear Yes Yes 5 UK BEAM51 Unclear Yes No No No No Yes Yes Yes Unclear Yes Yes Yes 7 Wright et al 54 Yes Yes No No No Yes No Unclear No Unclear Unclear Yes Yes 5