Vasculitis Damage Index (VDI)

The VDI is a clinician-assessed measure of permanent organ damage in patients with systemic vasculitis, including ANCA-associated vasculitis (AAV), polyarteritis nodosa, and other necrotising vasculitides. Introduced by Exley et al. (2003), VDI captures cumulative irreversible damage across organ systems, complementing disease activity measures (such as the Birmingham Vasculitis Activity Score). Systemic vasculitis is characterised by inflammation of blood vessel walls, leading to ischaemia and permanent tissue damage. VDI acknowledges that damage accrues over time and is largely irreversible, making it a prognostically important measure distinct from transient inflammatory activity.