Biopsychosocial determinants of physical and mental fatigue in patients with spondyloarthropathy.

The objectives of this study are to characterize fatigue in patients with spondyloarthropathy (SpA) using a multidimensional assessment and to delineate contributors to dimensions of fatigue. Fatigue in 125 participants with SpA was assessed using the Multidimensional Fatigue Inventory (MFI-20). Participants completed standardized questionnaires assessing sleep quality, depressed mood, perceived stress, social support, leisure time physical activity, functional capacity, and disease activity. Hierarchical multiple regressions were computed to identify contributors to physical and mental fatigue. Patients scored high on all five MFI-20 fatigue dimensions, with general fatigue and physical fatigue having the highest scores. A hierarchical multiple regression showed that worse functional capacity, greater perceived stress, more depressed mood and less participation in leisure time physical activity contributed to higher physical fatigue scores. The results of the second model found depressed mood to be the strongest determinant of mental fatigue, followed by poorer sleep quality and younger age. These findings indicate that fatigue in SpA is a multidimensional experience, with physical and mental aspects likely having different etiologies. A number of variables potentially amenable to treatment were found to be associated with physical and mental fatigue. A multidimensional assessment of fatigue in SpA is needed to tailor and optimize interventions aimed at alleviating fatigue.