EULAR/EUVAS definitions of disease states. From Hellmich, et al. Ann Rheum Dis 2007;66:605–17; with permission.

Absence of disease activity attributable to active disease qualified by the need for ongoing stable maintenance immunosuppressive therapy. The term “active disease” is not restricted to vasculitis only, but also includes other inflammatory features like granulomatous inflammation in WG or tissue eosinophilia in CSS.
50% reduction of disease activity score and absence of new manifestations.
Reoccurrence or new onset of disease attributable to active vasculitis.
Major relapse
Reoccurrence or new onset of potentially organ- or life-threatening disease.
Minor relapse
Reoccurrence or new onset of disease which is neither potentially organ- nor life-threatening.
Refractory disease
Unchanged or increased disease activity in acute AAV after 4 weeks of treatment with standard therapy in acute AAV.
Lack of response, defined as 50% reduction in the disease activity score, after 6 weeks of treatment.
Chronic, persistent disease defined as presence of at least 1 major or 3 minor items on the disease activity score list (e.g., BVAS or BVAS/WG) after > 12 weeks of treatment.
  • EULAR: European League Against Rheumatism; EUVAS: European Vasculitis Society; WG: Wegener’s granulomatosis; CSS: Churg-Strauss syndrome; AAV: antineutrophil cytoplasm antibody-associated vasculitides; BVAS: Birmingham Vasculitis Activity Score.