Clin Rheumatol. 2026 Apr 8. doi: 10.1007/s10067-026-08098-8. Online ahead of print.
ABSTRACT
OBJECTIVE: To investigate the impact of fear-avoidance beliefs, anxiety, and depression on disease activity in patients with ankylosing spondylitis (AS), focusing on pain as a mediator and exercise as a moderator.
METHODS: This cross-sectional study included 77 AS patients. We assessed disease activity using the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), pain via Visual Analog Scale (VAS), anxiety and depression with the Hospital Anxiety and Depression Scale (HADS), and fear-avoidance beliefs. We controlled for key covariates including age, gender, disease duration, functional status (HAQ), and medication use (biologic agents, antidepressants). Advanced statistical analyses included bootstrapped mediation (5,000 samples), moderated mediation, tenfold cross-validation, and robustness checks.
RESULTS: Abnormal anxiety (HADS-A ≥ 8) was present in 27.3% and abnormal depression (HADS-D ≥ 8) in 13.0% of patients. Pain was found to be a significant mediator in the pathway between fear-avoidance and BASDAI. The unstandardized indirect effect was 0.265 (95% CI [0.129, 0.446]), accounting for 49.1% of the total effect. This indirect pathway was significantly moderated by exercise, with the effect being stronger in low exercisers compared to high exercisers. A prediction model for high disease activity demonstrated strong discriminative ability (AUC = 0.863) with minimal overfitting confirmed by cross-validation (cross-validated AUC = 0.816).
CONCLUSION: Psychosocial factors are significant predictors of disease activity in AS. Our findings suggest that pain mediates the association between fear-avoidance beliefs and disease activity, a pathway that appears to be attenuated by regular exercise. These findings support a biopsychosocial approach in AS management. Future longitudinal studies are needed to confirm causal pathways. Key Messages • Fear-avoidance beliefs, assessed via a brief screening measure, are associated with disease activity in ankylosing spondylitis. • Pain partially mediates the relationship between fear-avoidance and disease activity, a pathway that is weakened by regular exercise. • Psychosocial screening and targeted interventions should be integrated into standard AS management.
PMID:41949713 | DOI:10.1007/s10067-026-08098-8
