Causal Mediation Analysis of the Effects of Pain Education on Disability and Pain Intensity in Individuals with Chronic Low Back Pain

Background/Objective: The purpose of this study was to determine whether the effects of pain education combined with physiotherapy could be explained by changes in psychological well-being and self-efficacy in individuals with chronic low back pain (LBP). Methods: This study includes a secondary analysis (mediation analysis) of a randomized controlled trial (RCT) that compares the effect of physiotherapy and pain education with physiotherapy alone. The Roland-Morris Disability Questionnaire, assessed at six weeks, was used as a primary outcome in this study, with pain intensity as a secondary outcome. The World Health Organization Five Well-Being Index (WHO-5) and the General Self-Efficacy Scale were evaluated as potential mediators. Causal mediation analysis based on a counterfactual framework was employed to estimate both direct and indirect effects. Results: The analyses comprised 46 participants (mean age = 42.2 years; 54.3% female) who received pain education along with physiotherapy. In the mediation models, improvements in emotional well-being (assessed by WHO-5) explained approximately one quarter of the effect of the intervention on disability (average causal mediation effect = −1.66, 95% CI [−2.8, −0.72], p < 0.001). By contrast, self-efficacy did not significantly mediate disability, and neither factor accounted for changes in pain intensity. Sensitivity analyses suggested that the indirect effect on psychological well-being was reasonably robust against potential unmeasured confounding factors. Conclusions: Enhancements in psychological well-being were associated with reductions in disability following pain education, whereas self-efficacy did not emerge as a significant mediator. These findings may support the value of incorporating mental well-being strategies within rehabilitation programs for chronic LBP.