Risk of acute arterial and venous thromboembolic events in Eosinophilic Granulomatosis with Polyangiitis (Churg-Strauss syndrome)

Background and objectiveSystemic small vessel vasculitides carry an increased risk of acute arterial and venous thromboembolic events (AVTE); however, this risk has not been systematically explored in Eosinophilic Granulomatosis with Polyangiitis (EGPA). This study assessed the occurrence and main risk factors of AVTE among EGPA patients as compared to the general community from the population-based Bruneck cohort.MethodsWe conducted a retrospective multicenter cohort study on 573 EGPA patients. Clinical and serological data were collected at diagnosis. Occurrence of AVTE and time to the first AVTE after EGPA diagnosis were recorded. Age-standardized event rate (SER) of AVTE as compared to the reference cohort was assessed. Cox regression was applied to identify AVTE predictors.Results129 EGPA patients (22.5%) had AVTE, considered as potentially life-threatening in 55.8%. Seventy patients experienced an AVTE prior to diagnosis (of whom 58.6% in the two years before diagnosis) and 75 following EGPA diagnosis, of whom 56% in the two subsequent years. The SER of AVTE as compared to the reference cohort was 2.10 (95% CI 1.67-2.63). This risk was particularly increased in patients with history of AVTE and with a Birmingham Vasculitis Activity Score ≥20 at diagnosis. Patients receiving immunosuppression within 2 months of diagnosis were at lower risk, while antiplatelet or anticoagulant treatment did not confer measurable benefit.ConclusionEGPA is associated with AVTE in approximately one quarter of patients, particularly around diagnosis. Immunosuppressants seemed to exert a protective effect, while anticoagulant and antiplatelet agents did not.