Effect modifiers of Cognitive-Functional Therapy in the treatment of chronic low back pain: secondary analysis of a randomized clinical trial

Abstract

Introduction: Low back pain is one of the leading causes of disability worldwide, and its chronicity involves psychosocial factors. Cognitive-Functional Therapy integrates physical, emotional, and behavioral components in pain management. Objective: To identify psychosocial and neurophysiological factors that may modify the response to Cognitive-Functional Therapy (CFT) compared to core training combined with manual therapy (CORE-MT) in patients with chronic low back pain, evaluating effects at 3, 6, and 12 months. Methods: Secondary analysis of a randomized clinical trial with 148 patients with chronic low back pain that compared the efficacy of CFT and CORE-MT in reducing pain and disability. The interventions were face-to-face and individual, with assessments before the intervention, post-intervention, and at 6 and 12 months. Results: High risk in StartBack was the only effect modifier of CFT in reducing disability (β = 7.83; 95% CI = 0.13 to 15.54; p = 0.046) and pain intensity (β = 1.67; 95% CI = 0.03 to 3.30; p = 0.044) post-intervention. The other variables (number of pain areas, anxiety, depression, social isolation, catastrophizing, fear of movement, stress, and risk in Örebro) did not show a modifying effect. At the 6-month follow-up, the results suggest that a high risk score on the StartBack modifies the effect of CFT treatment on disability reduction (β = 6.63; 95% CI = -0.76 to 14.03; p = 0.078) but not on pain intensity (β = 3.42; 95% CI = -5.32 to 12.17; p = 0.440). At the 12-month follow-up, no variable was an effect modifier. Conclusion: A high risk score on the StartBack modified the effect of CFT in reducing disability and pain in patients with chronic low back pain 3 months after the start of treatment and likely for disability 6 months after the start of treatment.