Work disability in patients with ankylosing spondylitis.

Objective: To determine the prevalence of work disability in Spanish patients with ankylosing spondylitis (AS) and to identify factors related to it.

Methods: A cross-sectional study based on data from Regisponser (National Spanish Registry of Patients with Spondyloarthropathy). Demographic and disease-related variables were collected. AS patients were classified as work-disabled according to the Spanish Social Security System criteria. Variables that discriminated between AS patients with and those without work disability were identified using chi-square test or unpaired t test when appropriate. Multiple logistic regression was performed.

Results: In total 699 AS patients, age 48.7 +/- SD 12.7 years and with disease duration 14.1 +/- 10.1 years, were analyzed; 179 patients (25.6%) had permanent work disability. Several variables had significantly different values in patients with compared to those without work disability. In the regression model (pseudo R(2) = 0.26, p < 0.0001), age (p = 0.001), sex (p = 0.04), disease duration (p = 0.006), total Bath AS Radiological Index (p = 0.007), Bath AS Functional Index (BASFI; p = 0.007), and chest expansion (p = 0.03) retained an independent association with work disability. When BASFI was excluded from the model the independent association with sex did not remain, and a significant association with finger to floor distance was found (p = 0.040).

Conclusion: The prevalence of permanent work disability in Spanish patients with AS is significant, and the main factors related to it are age, disease duration, structural damage, and physical functioning. Longitudinal studies are needed to confirm these results.