Systemic Lupus Erythematosus Disease Activity Score Remission and Low Disease Activity States Discriminate Drug From Placebo and Better Health‐Related Quality of Life

OBJECTIVE: Our objective was to evaluate the ability of Systemic Lupus Erythematosus Disease Activity Score (SLE-DAS) remission and low disease activity (LDA) to discriminate active drug from placebo and to discriminate outcomes in the patients' perspective (health-related quality of life [HR-QoL]) in SLE trials. METHODS: This was a post hoc analysis of the pooled Belimumab in Subjects With SLE (BLISS)-52 (NCT00424476) and BLISS-76 (NCT00410384) trials data. SLE-DAS remission and LDA attainment and discrimination between belimumab and placebo at 52 weeks were compared using chi-square tests. At week 52, 36-item Short Form Health Survey (SF-36) and Functional Assessment of Chronic Illness Therapy Fatigue (FACIT-F) scores were compared between patients attaining SLE-DAS remission versus nonremission and SLE-DAS LDA versus non-LDA using the t-test and Mann-Whitney test. Mean changes from week 0 to 52 in SF-36 and FACIT-F scores were compared between groups using multivariate regression analysis adjusted for baseline scores. RESULTS: At week 52, significantly more patients attained SLE-DAS LDA taking belimumab 1 mg/kg (17.9% vs 13.0%; P = 0.023; odds ratio [OR] 1.459; relative risk [RR] 1.377; number needed to treat [NNT] 20.4) and 10 mg/kg (21.7% vs 13.0%; P < 0.001; OR 1.853; RR 1.668; NNT 11.5) compared with placebo. Likewise, more patients attained SLE-DAS remission taking belimumab 10 mg/kg compared to placebo (14.7% vs 10.1%; P = 0.019; OR 1.532; RR 1.454; NNT 21.7). At week 52, patients attaining SLE-DAS remission and LDA presented higher SF-36 domain and summary scores (all P < 0.001) and FACIT-F scores (both P < 0.001). Mean improvements from baseline in SF-36 and FACIT-F scores were significantly higher in patients achieving SLE-DAS remission and LDA. CONCLUSION: SLE-DAS remission and LDA showed discriminant ability for identifying patients receiving active drug in SLE clinical trials. Attainment of these SLE-DAS targets are associated with better HR-QoL.