To the Editor:
Firstly, a disclosure. Drs. Urowitz, Gladman, and I have been discussing the optimal way(s) to capture lupus diseases activity since 1986! Sometimes we agree, sometimes not; but we try hard to keep it good-natured.
Their letter1, with due respect, does not really address the concerns expressed in my editorial2: that the Systemic Lupus Erythematosus Disease Activity Index 2000 Responder Index-50 (S2K RI-50) does not capture those patients whose symptoms which, having developed, then at the next assessment have got worse. Patients coming into clinical trials with, let us say, active arthritis or pleuritic pain will clearly get points on Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K) or S2K RI-50, but neither index will identify those patients given drugs and whose arthritis/pleuritis has deteriorated, or distinguish them from those whose symptoms have partially improved (by, let us say, 25%), or remained the same. That is the problem.
My friends and colleagues also miss the point about the British Isles Lupus Assessment Group index (BILAG)! Its scoring may be a little complex (although because, in clinical trials or on routine followup, the computer software does this, even scoring is not much of an issue). Further, the premise of BILAG, i.e., to ask patients with SLE, “Do you have a rash/joint problem/central nervous system feature etc., etc., and if you do, how has it been over the last month, better/worse/same?” is both simple and intuitive. BILAG provides a more comprehensive capture of SLE features than SLEDAI3, and if there is a need for metrics — well, they are available, using the validated conversion A = 12, B = 8, C = 1, D/E = 0, for the BILAG 2004 index4.