<h4>Background</h4>In this study, we investigated whether serum glutathione peroxidase-1 (GPX-3) concentration at diagnosis could be used to assess vasculitis activity and damage at diagnosis in immunosuppressive drug-naïve patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV).<h4>Methods</h4>We included 71 immunosuppressive drug-naïve patients newly diagnosed with AAV. Here, GPX3 is linked to vasculitis.