Outcome measures for Takayasu's arteritis

Takayasu's arteritis (TAK) is a large-vessel vasculitis with a chronic, indolent course affecting the aorta and its main branches. This review will describe the recent studies to develop validated outcome measures to assess TAK.

TAK is traditionally assessed with a physician's global assessment including symptoms and signs of inflammation and vascular insufficiency, acute-phase reactants (APRs), and imaging including conventional digital subtraction angiography, computerized tomographic, and magnetic resonance angiography, and recently 18-FDG-PET. Recent attempts to develop a validated tool for disease assessment include the Indian Takayasu Clinical Activity Score (ITAS2010), which incorporates clinical signs and symptoms with APRs in a simplified and weighted adoption of the Birmingham Vasculitis Activity Score. Among biomarkers to assess clinical activity, pentraxin-3 is perhaps the most promising, but its validity and superiority against APRs in clinical practice need to be demonstrated. Patient-reported outcomes (PROs) are increasingly recognized as of substantial importance to measure in clinical trials; in addition to so-called 'generic' tools such as the SF-36 or measures of fatigue, disease-specific instruments would likely help capture aspects of TAK not measured by generic quality-of-life assessments or physician-based tools.

Although outcome measures for TAK are not sufficiently validated, progress in the assessment of TAK is reflected in recent studies with new tools such as ITAS2010, new biomarkers, and a variety of PROs.