Characteristics of Severe Asthma Clinic Patients With Eosinophilic Granulomatosis With Polyangiitis.

Background: Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare form of antineutrophil cytoplasm antibody (ANCA)-associated vasculitis associated with varying clinical presentations and overlapping multiorgan involvement. Asthma is a predominant feature of EGPA, typically in its prodromal phase, often severe, and precedes vasculitic complications. However, there is paucity of studies describing the prevalence and characteristics of EGPA in the asthma population.

Objective: To describe the clinical and serological characteristics and longitudinal therapeutic outcomes of patients with EGPA in the severe asthma (SA) cohort.

Methods: A retrospective study of patients with EGPA attending the multidisciplinary SA clinic in a tertiary hospital from 2011 to 2023 was conducted. Baseline demographics, organ manifestations, biological markers, lung function, and therapeutic outcomes were assessed.

Results: Twenty-three of 596 patients in the SA registry were identified to have EGPA. Median time interval between asthma and EGPA diagnosis was 10 years (range, 2.5-32 years). Almost all patients (95.7%) had peak blood eosinophil count of more than 1.0 × 10⁹/L (range, 0.47-14.08 × 10⁹/L). Upper airway involvement was the most detected manifestation in addition to asthma, followed by neuropathy and renal involvement. Patients who were treated with biologic therapy were significantly younger and had more upper airway, renal, and pulmonary involvement and lower Five Factor Score.

Conclusions: The prevalence of EGPA in the SA population was 3.9% in our cohort. Its diagnosis requires high clinical suspicion in patients with SA and blood eosinophilia, prompting stringent evaluation for extrapulmonary manifestations and multidisciplinary involvement.