TY - JOUR T1 - Measuring Flares in Rheumatoid Arthritis. (Why) Do We Need Validated Criteria? JF - The Journal of Rheumatology JO - J Rheumatol SP - 189 LP - 191 DO - 10.3899/jrheum.131217 VL - 41 IS - 2 AU - AATKE van der MAAS AU - ALFONS A. den BROEDER Y1 - 2014/02/01 UR - http://www.jrheum.org/content/41/2/189.abstract N2 - In the treatment of rheumatoid arthritis (RA) it is of growing importance to measure disease activity both in clinical practice as well as in research. The last 20 years have brought us several well-validated disease activity indices: for example, the Disease Activity Score (DAS), DAS28 for 28 joints, the Clinical Disease Activity Index, and the Simplified Disease Activity Index are currently being used, and validated cutoff points to determine disease activity states as well as change criteria to indicate improvement to therapy have been developed1,2,3,4,5,6. However, in addition to measuring absolute disease activity states and improvement, there is an increasing need for assessing RA flare or worsening. Therefore, at the OMERACT 9 (Outcomes in Rheumatology) meeting a working definition of RA flare was proposed: flare occurs with any worsening of (or return of) disease activity that would, if persistent, lead to (re)initiation, increase or/and change of therapy; a flare represents a cluster of symptoms of sufficient duration intensity to require (re)initiation, change, or increase in therapy1. Although this working definition was an essential first step, research is needed on validated flare criteria, and the work of Bykerk, et al in this issue of The Journal represents an important contribution in the field7. Here, we would like to discuss several aspects of development and use of RA flare criteria.First, why do we need thoroughly validated flare criteria? The first scenario that exemplifies the need for a flare criterion is the use of fire-and-forget type of treatments such as rituximab, in which the timing of retreatment is often based on occurrence of a worsening in disease activity. Flare criteria are also essential in down-titration and discontinuation studies as well as … Address correspondence to Dr. van der Maas, Sint Maartenskliniek, Department of Rheumatology, Hengstdal 3, 6522 JV, Nijmegen, The Netherlands. E-mail: a.vandermaas{at}maartenskliniek.nl ER -