Kinesiophobia and Clinical Outcomes in People with Chronic Low Back Pain: A Cross-Sectional Study

Background/Objective: Kinesiophobia is a major fear-avoidance concept in chronic low back pain (CLBP); however, its independent contribution to pain, disability, and health-related quality of life (HRQoL) beyond sociodemographic and clinical variables remains unclear. This study aimed to evaluate the associations between kinesiophobia and patient-reported outcomes in adults with chronic low back pain regarding (i) pain intensity, (ii) functional disability, and (iii) HRQoL. Methods: This cross-sectional study included 298 participants with CLBP (average age 38.7 ± 13.2 years; 58.0% female). Kinesiophobia was evaluated using the Tampa Scale of Kinesiophobia (range, 17–68). Outcomes were pain intensity (Numerical Pain Rating Scale; 0–10), functional disability (Roland–Morris Disability Questionnaire; 0–24), and HRQoL (RAND-36; 0–100). Two multivariable linear regression models were used per outcome. Model 1 was adjusted for sex and age, and Model 2 was additionally adjusted for BMI, marital status, education, employment, smoking status, and chronic disease. Hierarchical regression analysis evaluated the incremental variance explained by kinesiophobia (ΔR2) when entered after all covariates. Effects were reported per 10-point increase in Tampa score, with 95% confidence intervals (CI). Results: In the fully adjusted models, higher kinesiophobia was associated with greater pain intensity (B = +1.17 points per 10 Tampa; 95% CI 0.55–1.79, p < 0.001), greater disability (B = +3.24 points; 95% CI 2.05–4.43; p < 0.001), and lower HRQoL (B = −7.98 points; 95% CI −11.1–−4.81; p < 0.001). Hierarchical regression analyses showed that kinesiophobia explained additional variance in pain (ΔR2 = 0.11), disability (0.12), and HRQoL (0.11), all p < 0.001. Conclusions: In adults with CLBP, kinesiophobia was associated with greater pain intensity, functional disability, and lower HRQoL, accounting for 11–12% of variance in each outcome beyond demographic and clinical covariates. These findings support routine assessment of kinesiophobia and justify longitudinal and interventional studies to determine temporal relationships and treatment effects.