Factors associated with disability in a sample of adults with arthritis

Background: Arthritis is the most common cause of disability among US adults. Few studies have comprehensively examined factors associated with disability in this population. Objective: To investigate the relationship between a number of disease and non-disease related factors and disability in sample of adults with self-reported doctor-diagnosed arthritis. Methods: Participants (n = 396) taking part in a randomized controlled trial of arthritis self-management completed a comprehensive survey assessing a number of demographic, arthritis-specific, health-related, behavioral, and psychological variables at baseline. Disability, as measured by the Health Assessment Questionnaire (HAQ), was also measured. Hierarchical regression models examined the independent associations between blocks of variables and disability. Results: Demographic variables (R-2 = 0.13), arthritis-specific demographics (i.e., type, medication use; Delta R-2 = 0.16), physical healthrelated variables (Delta R-2 = 0.06), arthritis-specific symptoms (Delta R-2 = 0.12), health behaviors (Delta R-2 = 0.00), and psychological variables (Delta R-2 = 0.03) explained 50% of the variance in disability score (R-2 = 0.50). With the exception of health behaviors, the addition of each block of variables significantly improved the model, explaining additional variance in HAQ scores (p < 0.0001). In the final model, older age, less than a high school education, rheumatoid arthritis, greater arthritis duration, taking steroids, taking narcotics, greater pain, greater stiffness, greater depressive symptoms, and lower arthritis self-efficacy were associated with greater disability whereas male gender, fibromyalgia, and excellent/very good health were associated with less disability. Conclusions: A number of disease and non-disease related variables were associated with disability. These findings suggest that disability in adults with arthritis may be a complicated phenomenon; such complexity may make decreasing disability in this population challenging. (C) 2013 Elsevier Inc. All rights reserved.