LAUSR

We read with great interest the publication entitled ‘EULAR definition of difficult-to-treat rheumatoid arthritis’, which sought not only to provide a uniform terminology, but also to formulate an adequate definition to classify those patients with difficult-to-treat rheumatoid arthritis (RA).1 Resolution of this issue promises to be very useful in clinical practice and in the design of studies for future research. Our group has recently published a study based on the clinical factors that could serve as possible predictors for identifying those patients with RA who are more susceptible to multiple failures to biological therapy.2 This study was designed and conducted prior to the publication of this paper establishing the definition of difficult-to-treat RA. Based on previous works published on this concept,3–8 we defined ‘multi-refractory’ patients as those who have received ≥2 biologic disease-modifying antirheumatic drugs (bDMARDs) with different mechanism of action or ≥3 bDMARDs with the same target. This definition seemed to us the most appropriate option for the classification of difficult-to-treat patients in terms of drug use. As the European League Against Rheumatism (EULAR) group of experts did, we did not include in our definition of multirefractory …