Illness perceptions and fatigue in systemic vasculitis

The idiopathic vasculitides are a group of rare, systemic diseases involving inflammation of arteries and other tissue with resulting organ- and life-threatening disease courses. The different forms of idiopathic vasculitis are typically classified based upon the predominant size of the arteries affected in each condition, including small vessel vasculitis [e.g. granulomatosis with polyangiitis (GPA, Wegener’s)]; medium vessel vasculitis [e.g. polyarteritis nodosa (PAN)]; and large vessel vasculitis [e.g. giant cell arteritis (GCA)]. Although patients with each type of vasculitis manage disease-specific aspects of illness, there are substantial disease and treatment burdens common to patients with vasculitis. For each type of idiopathic vasculitis, the disease course is often chronic, relapse is common and unpredictable, organ and tissue damage can accrue over time, new symptoms can occur late into the disease course, and treatment is often associated with toxicity and serious side effects. Illness perceptions, also called illness representations, are the organized beliefs that patients have about their illness. Based upon Leventhal’s Self Regulatory Model (1), it is theorized that patients consistently structure illness perceptions into common and measurable dimensions. Such dimensions include: beliefs about the symptoms that belong to the disease; the perception of the course the disease has and will have; beliefs on the impact of the illness on functioning and emotional well-being; beliefs on the degree of personal and treatment-based controllability of the disease; and the overall understanding of the condition. Illness perceptions have been found to be important determinants of health-related behavior and have been associated with important outcomes, such as treatment adherence and functional recovery, across a spectrum of diseases (2). Despite the substantial burdens of disease and treatment patients with vasculitis incur, illness perceptions have not been comprehensively assessed in systemic vasculitis. Understanding illness perceptions of patients with diverse forms of vasculitis may provide insight into the similarities and differences in the cognitive representations of disease and, as seen in other chronic diseases, may help explain important health-related behaviors and outcomes. Fatigue is a highly prevalent and an increasingly-recognized important manifestation of vasculitis, yet the mechanisms underlying fatigue are poorly understood. One study reported a finding of fatigue with a significant effect on life in approximately half of patients with vasculitis (3). In another study, fatigue was the most commonly reported symptom in a cohort of patients with vasculitis and was a principal contributor to impaired quality of life (4). As seen in other chronic diseases (5), fatigue is not well correlated with disease duration or with physician-derived measures of disease activity in vasculitis (3), suggesting that fatigue may be driven by psycho-social measures in response to disease. Further, illness perceptions may be associated with fatigue in vasculitis as has been demonstrated in other diseases (6). Interestingly, fatigue is considered one of the most important disease burdens by patients with vasculitis and is often rated as more burdensome than most manifestations of vasculitis that are associated with organ damage (7). This finding highlights potential different “models of illness” between patients with vasculitis and health professionals and suggests the importance of understanding illness from patients’ perspectives. The objectives of this study were 1) to compare illness perceptions of patients with a variety of forms of vasculitis; 2) to determine clinical and demographic variables associated with “negative illness perceptions” for vasculitis, defined as less-desirable perceptions about illness; and 3) to assess the association between illness perceptions and fatigue in vasculitis.