Objective: To determine factors associated with work in patients with ankylosing spondylitis (AS).
Methods: Three hundred fifteen patients with AS were enrolled in a 24-week, randomized controlled study of adalimumab with a longterm, open-label, adalimumab extension phase. Patient-reported outcome (PRO) measures included the Medical Outcome Study Short Form 36 Health Survey (SF-36), AS Quality of Life Questionnaire (ASQOL), Health Utilities Index Mark 3 (HUI-3), and Work Productivity and Activity Impairment-Specific Health Problem Questionnaire (WPAI-SHP). Multivariate logistic regression was used to analyze differences between working and nonworking patients. The relationships between PRO and WPAI-SHP scores were assessed using Pearson correlation coefficients. Multivariate modeling was applied to determine factors associated with productivity while at work. WPAI-SHP was assessed through 3 years of adalimumab exposure.
Results: Younger age (p = 0.002) and male sex (p < 0.001) were significantly and independently associated with working patients with AS. The SF-36 Physical Component Summary score (p < 0.001), ASQOL score (p < 0.001), HUI-3 scores (p < 0.001), and both patient's global assessment of disease activity (p < 0.001) and nocturnal pain (p < 0.001) scores were independently associated with working status. Work absenteeism due to AS was weakly correlated with all PRO scores. WPAI-SHP components of work presenteeism (lack of productivity at work), activity impairment, and overall work productivity loss due to AS were moderately correlated with quality of life as measured by the ASQOL, the SF-36 Physical Component Summary score, and the SF-36 Bodily Pain domain. Linear multivariate analyses indicated that work presenteeism was significantly associated with pain, functioning, and disease activity. Longterm adalimumab treatment was associated with sustained improvements in WPAI-SHP scores.
Conclusions: Quality of life and the physical consequences associated with AS have a direct relationship with a patient's ability to work. Adalimumab sustains improvements in work outcomes in patients with AS.