Clinical utility of the new ASAS criteria for spondyloarthritis and the disease activity score.

The advent of new therapeutic agents that are efficacious in the treatment of ankylosing spondylitis and related spondyloarthropathies has highlighted important unmet needs in our understanding of these conditions. Chief among these is the possibility of making a diagnosis at the early, nonradiographic phase, when the burden of disease is substantial and comparable to that of more advanced stages. The new Assessments in Spondyloarthritis International Society (ASAS) classification criteria provide a unique tool to allow research standardization in this area and may also be of clinical utility. The development of the disease activity index ASDAS (Ankylosing Spondylitis Disease Activity Score) aims to provide a composite measure that can discriminate and show sensitivity to change while incorporating measurable biomarkers. Both instruments represent a major step forward in the research field of spondyloarthritis, although further validation is now required.