Clinical Practice Audit on the Management of Antineutrophil Cytoplasmic Antibody–Associated Vasculitis in the Netherlands

Introduction: Managing complex and rare systemic autoimmune diseases such as antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) can be challenging and is often accompanied by undesirable variations in clinical practice. Adequate understanding of clinical practice can help identify essential issues to improve the care for AAV patients. Therefore, we studied the real-life management and outcomes of AAV patients in the Netherlands. Methods: In this cohort study, we investigated clinical practice in university and nonuniversity teaching hospitals with respect to patients with a clinical diagnosis of AAV. We retrospectively collected clinical data encompassing clinical variables, medication details, and outcome parameters. Results: Data of 230 AAV patients were collected in 9 Dutch hospitals. Of these, 167 patients (73%) were diagnosed with granulomatosis with polyangiitis, 54 (24%) with microscopic polyangiitis and 9 (4%) with eosinophilic granulomatosis with polyangiitis. One hundred sixty-six patients (72%) had generalized disease. The median year of diagnosis was 2013 (range 1987–2018). Besides steroids, oral cyclophosphamide was the most used drug (50%) for induction therapy and azathioprine (68%) for maintenance therapy. Adverse outcomes were major infections in 35%, major relapses in 23%, malignancy in 10%, major cardiovascular events in 8%, and end-stage renal disease in 7%. Conclusion: Oral cyclophosphamide was the most frequently used induction therapy, azathioprine for maintenance therapy; over time, the use of rituximab is increasingly employed. Major infection and relapses are the most prevalent adverse outcomes. This audit resulted in important indicators for treatment of AAV patients that can be implemented for future, national audits to improve the outcomes of AAV patients.