Mediators of the effect of cognitive-functional therapy on pain and disability in patients with chronic low back pain

Abstract

Introduction: Nonspecific chronic low back pain (DLCI) is a public health problem associated with a complex interaction between biopsychosocial factors. Cognitive Functional Therapy (CFT) is an intervention that addresses multidimensional aspects of pain that are potentially modifiable, such as provocative pain behaviors, movement and lifestyle changes. Considering the scarcity of studies on the role of psychosocial and lifestyle factors as potential mediators in the outcomes of pain and disability, identifying the mechanisms that explain the improvement of patients can contribute to the development of more effective interventions. Objective: To investigate potential mediators of the effect of CFT in patients with DLCI. Methods: Secondary analysis of a randomized controlled clinical trial with a blinded evaluator and allocation in two parallel groups (n = 148) and intention-to-treat analysis. Pain and disability were assessed at baseline and three months after randomization, as well as potential mediators (anxiety, social isolation, depression, fear of movement, catastrophization, stress and sleep disorders). The interventions were CFT in the experimental group and manual therapy combined with motor control exercises (TMEX) in the control group, with four to 10 sessions performed in a maximum period of three months in both groups. The analysis of potential treatment effect mediators was performed using causal mediation methods, using RStudio with a significance level of 5%. Results: The results showed that the “catastrophizing” mediator explained 41% (95% CI 10 to 100) of the disability improvement of the CFT group compared to the control group, while the “fear” mediator explained about 56% of the same improvement 56% (95% CI 25 to 100). For the pain outcome, there were no significant differences between the TCF and TMEX groups, and therefore, mediation analysis was not performed. Conclusion: Fear of movement and catastrophization were mediators of the effect of CFT in relation to the improvement of disability in patients with DLCI.