The relationship between anxiety, depression, and pain catastrophizing in patients with knee osteoarthritis and their impact on functional disability: A cross-sectional study.

Psychological distress, particularly anxiety and depression, is prevalent among KOA patients and may exacerbate functional disability through maladaptive cognitive processes such as pain catastrophizing. This study examined whether pain catastrophizing mediates the relationship between psychological distress and functional disability in KOA patients. We enrolled 90 KOA patients between January 2024 and January 2025. Anxiety (GAD-7), depression (PHQ-9), pain catastrophizing (Pain Catastrophizing Scale, PCS), functional disability (WOMAC), and pain intensity (visual analog scale, VAS) were assessed. Pearson correlation, hierarchical regression, and bootstrap-based mediation analyses were performed. The mean age was 61.77 ± 7.63 years, and 58.9% were female. Anxiety (GAD-7: 8.58 ± 4.68), depression (PHQ-9: 8.92 ± 5.31), and pain catastrophizing (PCS: 23.59 ± 10.43) were moderately elevated. All psychological variables were significantly correlated with WOMAC scores (r = 0.464-0.637, P < 0.001). Hierarchical regression showed psychological variables significantly increased explained variance in functional disability (ΔR2 = 0.095, P < 0.001). Mediation analysis revealed pain catastrophizing partially mediated the anxiety-disability relationship (indirect effect = 0.816, 95% CI [0.425, 1.256], proportion mediated = 48.5%) and fully mediated the depression-disability relationship (indirect effect = 1.028, 95% CI [0.557, 1.636], proportion mediated = 65.0%). Within these cross-sectional data, pain catastrophizing statistically mediated the associations of anxiety and depression with functional disability; because temporal precedence cannot be established, these relationships should be interpreted as associational rather than causal. The findings nonetheless identify pain catastrophizing as a potentially modifiable cognitive correlate of disability and support evaluating cognitive-behavioral interventions targeting catastrophizing within comprehensive KOA management.