Functional disability in chronic lumbar disc herniation: Associations with pain intensity, health literacy, and psychosocial factors—a multicentre cross-sectional study

BackgroundFunctional disability in chronic lumbar disc herniation may reflect interacting clinical, psychosocial, and socioeconomic factors. The role of health literacy and its potential indirect associations with disability remain unclear.ObjectiveTo examine associations of health literacy, kinesiophobia, anxiety, depressive symptoms, and pain intensity with functional disability and to explore indirect associations between health literacy and disability.MethodsThis multicentre cross-sectional study included 148 adults with chronic low-back pain and MRI-confirmed lumbar disc herniation. Disability, health literacy, kinesiophobia, anxiety, depressive symptoms, and pain intensity were assessed using validated measures. Associations were examined using Spearman correlations, HC3-robust multiple linear regression, and exploratory parallel indirect-association analyses with 10,000 bootstrap resamples.ResultsThe regression model explained 50.0% of the variance in Oswestry Disability Index scores. Pain intensity showed the strongest association with disability and was the only independently associated factor (B = 4.71; β = 0.587; p < 0.001). Health literacy was not directly associated with disability. The combined indirect association through kinesiophobia, anxiety, and depressive symptoms was statistically significant in the unadjusted model (B = -0.323; 95% CI, -0.505 to -0.143), whereas after adjustment for pain intensity the estimate was attenuated and the confidence interval included zero (B = -0.128; 95% CI, -0.266 to 0.020). Higher educational attainment and income were independently associated with higher health literacy.ConclusionPain intensity was most strongly associated with functional disability. Health literacy was not directly associated with disability but was associated with educational attainment and income. Prospective studies should clarify these relationships.