OBJECTIVES: To estimate the costs associated with refractory Eosinophilic Granulomatosis with Polyangiitis (EGPA) treatment from the Brazilian public health system perspective.

METHODS: This was qualitative research in which expert interviews were utilized to estimate healthcare resource use and, therefore, costs of EGPA management in the public health system in Brazil. The methodology consisted of a four-hour virtual panel in June 2023 with five experts: rheumatologists with years of experience in the field and a history of eight patients with EGPA, on average, treated in the last 12 months of clinical practice. The discussion was guided by a questionnaire, previously shared, regarding required patient resources to treat this severe disease through the Brazil's public health system. After defining resource use standards, each cost item was valued according to governmental price sources.

RESULTS: Per patient in remission, the quarterly follow-up cost was estimated at BRL 151.97, including medical consultations, laboratory and imaging tests, and medications. Costs per patient with minor relapse was BRL 848.23 each quarter (four months), with follow-up exams, medications, and emergency visits being the main expenses. Severe relapse demand additional resources, BRL 20,297.71 per quarter, of which 77% are spent on hospitalizations and 16% on diagnostic procedures. Refractory disease would require BRL 9,228.58 per quarter.

CONCLUSIONS: The costs of treating EGPA are linked to the severity of the disease: the more severe it is, the more days of hospitalization, which is the main component of costs mapped. This work sheds light on an understudied topic in Brazil and lacks economic evaluations worldwide.