Abstract
Objective Fatigue is one of the most significant symptoms, and an outcome of great importance, in patients with psoriatic arthritis (PsA), but associations between underlying components of fatigue experienced by patients in relation to the disease have been sparsely investigated. The objectives were to describe the degree of fatigue in PsA patients, and secondly to explore important components associated with fatigue.
Methods We performed a cross-sectional survey including patients registered in the Danish nationwide registry DANBIO from December 2013 to June 2014. Principal component analysis was used to identify factors associated with fatigue.
Results A total of 1,062 PsA patients were included in the study. A principal component analysis reduced co-variables into three components explaining 63% of fatigue in patients. The first component, contributing to 31% of fatigue, was composed of inflammatory factors including swollen and tender joints, doctors’ global assessment, elevated CRP, and high Pain Detect Questionnaire (PDQ) score; the second component, contributing to 17%, consisted of increasing age and long disease duration. The third component, contributing to 15%, consisted of high PDQ score, tender joint count, increasing age, and concomitant low CRP, suggestive of a chronic pain component consisting of central pain sensitization or structural joint damage.
Conclusion Fatigue in PsA patients may be driven by clinical inflammatory factors, disease duration, and chronic pain in the absence of inflammation.
