Effectiveness of Cognitive Behavioral Therapy, Physical Therapy, and TNF Inhibitors in Managing Chronic Lower Back Pain in Ankylosing Spondylitis Patients: A Randomized Controlled Trial

Abstract

Background: Ankylosing spondylitis (AS) is a chronic inflammatory rheumatic disease primarily affecting the axial skeleton, leading to persistent lower back pain, functional impairment, and diminished quality of life. Tumor necrosis factor (TNF) inhibitors are established as effective treatments for controlling inflammation and slowing disease progression, yet they inadequately address the psychological and physical dimensions of chronic pain. Non-pharmacological interventions, such as physical therapy (PT) and cognitive behavioural therapy (CBT), offer potential complementary benefits; however, robust evidence from randomized controlled trials (RCTs) evaluating their combined efficacy with TNF inhibitors remains scarce. Objective: To determine whether a multidisciplinary approach integrating TNF inhibitors, PT, and CBT yields superior improvements in pain intensity, functional status, quality of life, and inflammatory biomarkers compared to TNF inhibitors alone or PT plus CBT in adults with AS and chronic lower back pain. Methods: This single-center RCT enrolled 45 adults (aged 18–60 years) with AS (per modified New York criteria) and chronic lower back pain (≥6 months). Participants were randomized equally (1:1:1) to one of three arms: TNF inhibitors alone, PT + CBT, or TNF inhibitors + PT + CBT. Outcomes were assessed at baseline and after an 8-week intervention using the Numeric Rating Scale (NRS) for pain (0–10), Bath Ankylosing Spondylitis Functional Index (BASFI, 0–10) for function, Ankylosing Spondylitis Quality of Life (ASQoL, 0–18) questionnaire for quality of life, and serum C-reactive protein (CRP, mg/L) and erythrocyte sedimentation rate (ESR, mm/hr) as inflammatory biomarkers. Statistical analysis employed one-way ANOVA with post-hoc Tukey tests, adjusted for multiplicity using the Holm-Bonferroni method, with a significance threshold of p<0.05. Results: Baseline characteristics were balanced across groups. Post-intervention, the TNF inhibitors + PT + CBT group exhibited significantly greater improvements compared to single-modality groups: NRS (mean change -4.3 ± 1.3 vs. -2.2 ± 1.3 and -1.7 ± 1.3; F=12.362, p<0.001, η²=0.37), BASFI (-3.3 ± 1.2 vs. -1.3 ± 1.2 and -1.4 ± 1.2; F=21.590, p<0.001, η²=0.51), ASQoL (-7.4 ± 2.3 vs. -2.7 ± 2.5 and -4.3 ± 2.4; F=44.499, p<0.001, η²=0.68), CRP (-12.3 ± 3.4 vs. -7.2 ± 3.5 and -4.0 ± 3.6 mg/L; F=26.271, p<0.001, η²=0.56), and ESR (-21.5 ± 7.4 vs. -12.5 ± 7.5 and -7.0 ± 7.6 mm/hr; F=19.010, p<0.001, η²=0.48). Adherence rates were high (80% in combined and TNF inhibitor arms, 66.7% in PT + CBT). Conclusion: A multidisciplinary intervention combining TNF inhibitors, PT, and CBT provides superior short-term benefits in pain, function, quality of life, and inflammation control compared to monotherapy or dual therapy in AS patients. These findings support the adoption of integrated care models, though larger, multicentre trials with long-term follow-up are needed to confirm durability and generalizability.