Damage assessment in ANCA-associated vasculitis

Antineutrophil cytoplasm antibody associated vasculitis has been transformed from life-threatening conditions to chronic relapsing long-term diseases as a result of significant advances in immunosuppressive therapy. Although mortality still occurs, it is much less frequent, with an average 5-year survival of over 70 %. In the setting of chronic conditions, it becomes increasingly important to monitor the burden of disease in terms of both active inflammation requiring immunosuppression and chronic damage (scarring) from vasculitis and its treatment and associated comorbidity. The damage that accumulates in patients with vasculitis does not respond to immunosuppressive treatment. It is important to distinguish disease activity from disease damage to prevent unnecessary immunosuppression, but it is equally important to recognize damage for what it is, so that it can be addressed appropriately. Damage is an inevitable consequence of long-term vasculitis for over 80 % of patients, which should not surprise us given the severity of the original illness. There is potential value in measuring damage as a means of providing prognostic information. Using a quantified score such as the Vasculitis Damage Index (VDI) allows us to predict mortality. Patients with at least five items of damage on the VDI score have substantially worse mortality (7- to 11-fold worse risk), as compared with those with lesser amounts of damage. These findings should be taken into context when planning the management of patients with vasculitis, as well as in clinical trials of vasculitis. Disease damage is an important surrogate for long-term outcome in vasculitis, and studies should be designed to limit the amount of damage accumulating as a result of therapeutic intervention, rather than simply controlling disease activity, as is currently the aim in recent randomized controlled trials in vasculitis. Furthermore, careful cataloguing of damage, as well as disease activity items, provides much greater detail in describing and observing the long-term natural history of primary systemic vasculitis in patients treated with immunosuppressive agents who survive their initial disease process.