Difficult-to-treat, complex-to-manage, treatment-refractory spondyloarthritis: semantics or substance?
PURPOSE OF REVIEW: The concept of difficult-to-treat (D2T) disease is increasingly recognized across immune-mediated inflammatory diseases, and was recently introduced in spondyloarthritis (SpA). Several terms, including difficult-to-manage (D2M), complex-to-manage (C2M), and tr…