Objective. Patients vary in their beliefs related to the cause of serious illness. The effect of these beliefs among patients with systemic vasculitis is not known. Our study aimed to describe causal attributions about disease onset and relapse in systemic vasculitis and to examine whether causal beliefs differ by type of vasculitis or are associated with negative health outcomes.

Methods. Patients with vasculitis were recruited to complete an online questionnaire. Categories of causal beliefs were assessed with the Revised Illness Perception Questionnaire (IPQ-R). Differences in beliefs about disease onset versus relapse were compared across different forms of vasculitis. Causal beliefs were assessed in association with several health outcomes including fatigue, functional impairments, and personal understanding of the condition.

Results. The questionnaire was completed by 692 patients representing 9 forms of vasculitis. The majority (90%) of patients had beliefs about the cause of their illness. Causal attributions were highly variable, but altered immunity and stress were the most commonly agreed-upon causal beliefs. Frequencies of causal beliefs were strikingly similar across different forms of vasculitis, with a few notable exceptions primarily in Behcet disease. Beliefs differed about causes of disease onset versus relapse. Specific beliefs about disease onset and relapse were weakly associated with fatigue, functional impairments, and understanding of the condition.

Conclusion. Patient beliefs related to the cause of systemic vasculitis are highly variable. Patterns of causal beliefs are associated with important negative health outcomes. Clinicians who care for patients with vasculitis should be mindful of these associations and consider asking about patients' causal beliefs.