Anti-neutrophil cytoplasmic antibody-associated vasculitis: prevalence, treatment, and outcomes

Anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV) is a primary small-vessel vasculitis group with three distinct clinical entities, including GPA, MPA, and EGPA. The incidence of AAV has increased since the 1980s and remained stable since the early 2000s. Distinct phenotypes of AAV may also differ in various geographical regions. Elderly people are susceptible to developing AAV, and AAV is used to be a fatal disease before the introduction of glucocorticoids and immunosuppressants. Different treatment protocols should be employed for patients with different disease severity levels. Several randomized controlled trials evaluated the efficacy and safety of treatment protocols for remission induction and maintenance. Glucocorticoid and cyclophosphamide therapies remain the mainstay for treating AAV. Rituximab is non-inferior to cyclophosphamide for inducing remission, and it is more effective for relapsing and refractory disease. The combination of low-dose glucocorticoids with less toxic immunosuppressants, such as azathioprine, rituximab, and methotrexate, is suggested in place of cyclophosphamide. The prognosis of patients with AAV is another crucial issue due to the accumulating damage caused by both the disease activity and treatment toxicity. This review focused on recent progress on the prevalence, treatment, and outcomes of patients with AAV.