Fig. 1

Forest plot with results for RMDQ (primary outcome). The difference in mean RMDQ score between the treatment groups (size of treatment effect) with 95% confidence interval is shown in black on the right for each of the two categories of each potential effect modifier. The difference in size of treatment effect between the two categories (estimated by the interaction term), with 95% confidence interval and p-values is shown in red. RMDQ Roland-Morris Disability Questionnaire. Score from 0 to 24. Higher scores indicate more severe pain and disability. CRP C-reactive protein. ODI Oswestry Disability Index. Score from 0 to 100. Higher scores indicate more severe pain and disability. LBP Low back pain