Performance of SLE responder index and lupus low disease activity state in real life: A prospective cohort study

Abstract

Objective: To prospectively assess the performance of the systemic lupus erythematosus (SLE) responder index (SRI) and the lupus low disease activity state (LLDAS) in a cohort-based, "real-life" clinical setting.

Methods: One hundred and thirty-one consecutive patients with SLE were subdivided into two groups based on the need or not to escalate their immune suppressive treatment. Clinimetrics including physician global assessment scale (PGA), SLE Disease Activity Index 2000 (SLEDAI-2K), European Consensus Lupus Activity Measurement index (ECLAM) and British Isles Lupus Assessment Group index (BILAG) 2004 version were measured at baseline and at 6 and 12 months, together with laboratory data and treatment changes. LLDAS and SRI were calculated at each time point.

Results: Lupus low disease activity state but not SRI-4 correlated with treatment de-escalation. Low disease activity attainment as estimated by LLDAS was more frequent in patients starting with lower SLEDAI-2K, whereas a decrease in SLEDAI score ≥ 4 points with < 0.3 increased PGA and no new grade A or more than one new grade B BILAG domains (SRI-4) was more frequent in patients with higher SLEDAI-2K and/or severe renal activity at baseline. Anti-DNA-positive patients were less likely to be in LLDAS at any time point. Serositis was associated with lack of LLDAS at baseline, but did not affect LLDAS achievement at 12 months. Normalizing complement levels heralded the achievement of LLDAS and SRI-4.

Conclusion: Lupus low disease activity state is a valuable tool for assessing response to treatment in the daily rheumatology practice. SRI might be less informative, at least in patients with low basal SLEDAI.

Keywords: clinimetrics; disease activity; index; lupus; lupus low disease activity state; response; scale; systemic lupus erythematosus; systemic lupus erythematosus responder index; treatment.