Factors Associated With Fatigue In Patients With Rheumatoid Arthritis: A Multidimensional "Path Analysis" Model

Background Fatigue is one of the most commonly reported symptoms in rheumatoid arthritis (RA) and severe fatigue also occurs in patients with low disease activity. Many factors may play a role in causing fatigue in RA. Several cross-sectional and longitudinal studies showed that psychosocial factors such as self-efficacy and coping strategies, pain and limitations in daily functioning, rather than inflammation, are related to fatigue severity in RA (1-4). These factors could have a possible causal relationship with fatigue. Objectives To develop and test a multidimensional model of factors that determine fatigue severity (CIS-fatigue) in RA using “path analysis”, with the aim to facilitate the development of a treatment strategy for RA fatigue. Methods A cross-sectional study (n=228) of consecutively included patients with RA was performed. Patient and disease characteristics, fatigue level, personality factors and psychosocial variables were collected (fig 1). Structural equation modeling (“path analysis”) was used to test a hypothesized model for fatigue. The hypothesized model of fatigue included latent variables of pain, physical functioning, mood, sense of control, sleep disturbances and fatigue. Results The final model included 4 latent variables and had a moderate fit (CFI=0.943) (figure 1). According to the model a higher pain level (β=0.16, p=0.274) and lower physical functioning (β=-0.61, p=0.002) leads to a higher fatigue level. In addition, more mood disturbance is related to a higher fatigue level (β=0.253, p=0.003) and a worse sense of control is related to more mood disturbance (β= -0.58, p≤0.001). The final model including pain, mood and physical functioning explained 72% of the variance of fatigue in RA. Conclusions According to the multidimensional model, RA fatigue is influenced by pain, sense of control, mood and physical functioning. Treatment of these four factors by psychological interventions and an exercise program could help to improve fatigue in patients with RA. Randomized controlled trials, are needed to test the efficacy of these interventions. References Hewlett S, Chalder T, Choy E, Cramp F, Davis B, Dures E, et al. Fatigue in rheumatoid arthritis: time for a conceptual model. Rheumatology (Oxford). 2011;50(6):1004-6. Epub 2010/09/08. van Hoogmoed D, Fransen J, Bleijenberg G, van Riel P. Physical and psychosocial correlates of severe fatigue in rheumatoid arthritis. Rheumatology (Oxford). 2010;49(7):1294-302. Epub 2010/04/01. Treharne GJ, Lyons AC, Hale ED, Goodchild CE, Booth DA, Kitas GD. Predictors of fatigue over 1 year among people with rheumatoid arthritis. Psychol Health Med. 2008;13(4):494-504. Epub 2008/10/01. Mancuso CA, Rincon M, Sayles W, Paget SA. Psychosocial variables and fatigue: a longitudinal study comparing individuals with rheumatoid arthritis and healthy controls. J Rheumatol. 2006;33(8):1496-502. Epub 2006/06/20. Disclosure of Interest : None declared DOI 10.1136/annrheumdis-2014-eular.1637