Background:ANCA associated vasculitis (AAV) is a complex, rare systemic autoimmune disease with an estimated prevalence of 5-18 patients per 100.000 individuals worldwide. Managing a low prevalent disease can be challenging which is reflected in clinical practice variation.Objectives:This study investigated clinical practice variation of the care for AAV patients in the Netherlands.Methods:In a nationwide online survey, AAV patients were selected from academic and non-academic centers. Within centers, patients were eligible when they had a confirmed diagnosis of microscopic polyangiitis (MPA), granulomatosis with polyangiitis (GPA) or eosinophilic granulomatosis with polyangiitis (eGPA) according to the treating physician. There were no exclusion criteria. In each center a comparable number of patients was included. Data capture encompassed a wide set of variables on diagnosis, management and outcomes.Results:From December 2018 to November 2019, 230 AAV patients were recruited in 6 non-academic and 3 academic hospitals (120 vs 110 patients respectively). Differences in clinical diagnoses (GPA, MPA and eGPA) were observed between non-academic and academic centers (p=0.05), which was mainly caused by a higher number of MPA patients in non-academic centers. The year of diagnosis was comparable (median 2013 [2009-2016], p=0.150). The median follow up since diagnosis was 4.8 years [1.8-9.6] with a median in-hospital time-to-diagnosis of 13 days [2-50]. Patients were diagnosed at a mean age of 63 years (±11.18) in non-academic centers and 53 years (±16.92) in academic centers (p<0.001). Besides steroids, oral cyclophosphamide was the most preferred drug (54%) for induction therapy, whereas rituximab was given significantly more often as (part of the) induction therapy in patients treated in academic centers compared to patients in non-academic centers (27% vs 8%, p<0.001). In non-academic centers pneumocystis pneumonia (PCP) prophylaxis was prescribed significantly less (76% vs 91%, p=0.003). Also, screening for Staphylococcus aureus carriership was significantly less (17% vs 68%, p<0.001). With respect to mortality and co-morbidity, 22 patients (10%) died, 100 patients (44%) had at least one infection and 24 patients (10%) suffered from at least one malignancy. We observed no significant differences on these endpoints between academic and non-academic centers.Conclusion:The present study highlights important practice variation in the management of AAV between academic and non-academic hospitals in the Netherlands. A high proportion of patients is treated with oral cyclophosphamide as induction therapy while rituximab is increasingly used in academic centers. Rates of mortality, infections and malignancies were not different. Altogether, this study raises awareness into the variation of management for AAV patients and allows the identification of areas for improvement of clinical care for Dutch AAV patients.Disclosure of Interests:Ebru Dirikgil: None declared, Abraham Rutgers: None declared, Sander Tas: None declared, Cornelis A. Verburgh: None declared, Darius Soonawala: None declared, A. Elisabeth Hak: None declared, Hilde H.F. Remmelts: None declared, Daphne IJpelaar: None declared, Gozewijn D. Laverman: None declared, Jacob M. van Laar Grant/research support from: MSD, Genentech, Consultant of: MSD, Roche, Pfizer, Eli Lilly, BMS, H.J. Bernelot Moens: None declared, Peter Verhoeven: None declared, Willem Jan W. Bos: None declared, Y.K. Onno Teng Grant/research support from: GSK, Consultant of: GSK, Aurinia Pharmaceuticals, Novartis