Clinical Presentation and Outcomes of Eosinophilic Granulomatosis with Polyangiitis in Chinese Patients: Insights from a Multicenter Retrospective Cohort

Objective: Eosinophilic granulomatosis with polyangiitis (EGPA) is a form of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis. Data among Chinese patients is sparse. This multicenter retrospective study aims to assess the presentation, treatment strategies, and outcomes of EGPA in Hong Kong. Methods: Patients with newly diagnosed EGPA who presented to eight participating hospitals in Hong Kong between January 1, 2013 and December 31, 2023 were identified. Clinical history and laboratory parameters were collected and analyzed. Outcomes, including mortality, relapse, and complications from disease and treatment, were assessed. Results: Seventy-six patients were identified. The annual incidence of EGPA was estimated at 1.9 per million population. Regarding the presentation, neurological symptoms (71.1%) were most frequently observed, followed by cutaneous (54%) and pulmonary symptoms (52.6%). The presence of anti-myeloperoxidase antibody (anti-MPO) correlated with a higher Birmingham Vasculitis Activity Score (BVAS) on presentation, more renal involvement, and absence of asthma. While anti-PR3 was associated with cardiovascular manifestations. Treatment mainly involved corticosteroids and cyclophosphamide as induction and azathioprine as maintenance. Biologics were used for induction in 18.4% of cases and for maintenance in 7.9%. Infective complications occurred in 29% of patients; a starting prednisolone dose [Formula: see text] 40 mg daily and a history of diabetes mellitus were identified as risk factors. Relapses occurred in 26.3% of subjects; the mean time to relapse was 39.5 months. Multivariate survival analysis revealed that a history of smoking [Formula: see text] 1 year (HR 20.63, 95% CI 2.76–154.37, [Formula: see text] = 0.03), absence of asthma (HR 0.13, 95% CI 0.02–0.96, [Formula: see text] = 0.045), and absence of neurological involvement on presentation (HR 0.06, 95% CI 0.01–0.45, [Formula: see text] = 0.006) were associated with mortality. Conclusion: This study underscored the heterogeneity of EGPA in the Chinese population and supports categorization based on anti-MPO status. Smoking history and absence of asthma or neurological symptoms were associated with mortality. The findings aim to inform clinical practice and direct future research efforts in managing this complex disease.