Outcome measures in primary systemic vasculitis

The primary systemic vasculitides are complex multisystem disorder where accurate assessment of disease activity and disease damage is difficult. In order to evaluate therapies in clinical trials good outcome measures are necessary. In ANCA associated vasculitis (AAV), clinical checklists such as the BVAS are used to measure disease activity and the VDI to measure disease and treatment related damage. These tools were developed by consensus expert opinion; have been used for over a decade in clinical trials and are now well-validated and accepted measures. The availability of good outcome measure was a key factor in enabling therapeutic trials in AAV. OMERACT has endorsed a 'core set' of domains for trials in AAV with validated measures in each domain. In contrast, there has been an absence of outcome measures in large vessel vasculitis and as a consequence almost no clinical trials in giant cell arteritis or Takayasu's arteritis to date. The landscape may be changing with improved imaging techniques and the recent development of the Indian Takayasu's Arteritis Activity Score (ITAS2010). OMERACT has a working group to try and develop and validate outcome measures for large vessel vasculitis, which provides an opportunity for interested researchers to be involved in this process.