Disease activity and damage scores

GPA disease activity was assessed using the Birmingham Vasculitis Activity Score Modified for Wegener’s Granulomatosis (BVAS/WG), an established tool for clinical use and research that measures disease activity, vasculitis treatment outcomes, and the prognosis. The BVAS/WG measures activity according to 34 items that are categorized into 9 groups. The BVAS/WG values range from 0 to 63. Disease activity was defined as a BVAS/WG score ≥1, and remission was defined as a BVAS/WG score of 0 ¹⁹. ANCA positivity was assessed using an indirect immunofluorescence method and was also used as a parameter of disease activity ²⁰.

The Vasculitis Damage Index (VDI) was used to assess damage in all patients. The VDI is a validated checklist of 64 items divided into 11 organ-based systems and an ‘other’ category corresponding to potential treatment side effects. An item of damage was only recorded if it occurred after the onset of vasculitis and was considered permanent, defined as persistence for more than 3 months. In patients with established comorbidities prior to vasculitis, an item was only recorded if it had deteriorated significantly within at least 3 months since disease onset ²¹.