Disease assessment in systemic vasculitis.

The anti-neutrophil cytoplasm antibody-associated vasculitides are complex multi-system disorders with many overlapping clinical features. Their outcome has been transformed by effective immunosuppression, preventing death in over 70% of cases. The quality of survival is affected by the disease course, which is characterized by a significant likelihood of relapse in 38%, chronic effects from the disease and its treatment, as well as emerging or worsening comorbidity, all of which contribute to the patient's clinical condition and outcome. Whilst imaging and laboratory testing including histology are important aspects of diagnosis, they are of limited value in assessing response to therapy or subsequent disease course. We have developed standardized validated clinical methods to quantify disease activity and damage; we are developing effective measures of patient experience to complement these procedures. This approach provides a rational basis for clinical management as well as being essential in the conduct of clinical trials and studies in vasculitis, by providing reproducible definitions of relapse, remission and response to therapy for patients with systemic vasculitis. Clinical assessment remains the current gold standard for evaluating disease progress, but requires regular training to ensure standardization. The development of biomarkers in future may produce a more accurate description of disease and identify potential targets for therapy as well as predictors of response to drugs.