AB1003 CHANGE IN DISEASE ACTIVITY OF SYSTEMIC LUPUS ERYTHEMATOSUS: VALIDATION OF THE SLE DISEASE ACTIVITY SCORE (SLE-DAS) IN A LONGITUDINAL COHORT
Authors: C. H. To, C. C. Mok, F. Lam
Journal: Annals of the Rheumatic Diseases (2024)

<h3>Background:</h3> The Systemic Lupus Erythematosus Disease Activity Score (SLE-DAS) is validated in Italian patients with SLE. It has been shown to be sensitive to change compared to Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K). There are no longitudinal data in Chinese patients with SLE. <h3>Objectives:</h3> To validate the sensitivity to change of disease activity of the SLE-DAS in a longitudinal cohort of Chinese patients with SLE. <h3>Methods:</h3> Consecutive patients with active SLE (Physician Global Assessment [PGA]&gt;1.0) were recruited from our out-patient clinics and hospital admissions between March and December 2023. Assessment of disease activity (PGA, SLEDAI-2K and SLE-DAS) were performed at baseline and month 6 by the same team of physicians. The SLE response index (SRI-4), Definitions of Remission in SLE (DORIS) remission on therapy (clinical SLEDAI=0, PGA &lt;0.5, prednisolone ≤5 mg/day, stable antimalarials, immunosuppressive drugs and biologics), low disease activity state (LLDAS), and SLE-DAS boolean-based remission (clinical item of SLE-DAS=0 and prednisolone ≤5mg/day) at month 6 was evaluated. A change in PGA by ≥0.3 was defined as a clinically relevant change in disease activity. A change of SLEDAI-2K ≥4 and SLE-DAS ≥1.72 (as validated in Italian patients) were tested for their sensitivity and specificity against a change of PGA ≥0.3. <h3>Results:</h3> 500 patients were assessed; 416 (83.2%) had PGA ≤1.0 at baseline. All were ethnic Chinese. An interim analysis of 61 patients with active SLE (PGA &gt;1) who had completed the 6-month visits was performed. The mean age was 41.8±10.8 years and 92% were women. The commonest active SLE manifestations at baseline were proteinuria (42.6%), skin lesions (36.1%), arthritis (18.0%), leukopenia (13.1%) and thrombocytopenia (6.5%). There were 51 patients who had change of PGA ≥0.3: 5 episodes were worsening and 46 episodes were improving. An improvement in SLE-DAS ≥1.72 was observed in 35 (57.3%) patients. A SLE-DAS change of ≥1.72 showed a significantly higher sensitivity to detect a change in PGA ≥0.3 compared to SLEDAI-2K ≥4 points (80.3% vs 43.1%, p&lt;0.01). Both the specificity of SLE-DAS ≥1.72 and SLEDAI-2K ≥4 in the detection of PGA≥0.3 were 100%. A total of 22 (36.1%) patients achieved SRI-4 at month 6, and all were captured by a reduction of SLE-DAS by ≥1.72. The proportions of patients who achieved DORIS remission on therapy, SLE-DAS boolean-based remission and LLDAS were 15 (24.5%), 19 (31.1 %) and 26 (42.6%), respectively. <h3>Conclusion:</h3> The SLE-DAS is significantly more sensitive than SLEDAI-2K in the identification of a clinically relevant change in SLE activity by PGA, while specificity is preserved. It shows similar performance to DORIS in the identification of remission. The SLE-DAS shows potential for use as a treatment endpoint in future SLE therapeutic trials. <h3>REFERENCES:</h3> <b>NIL.</b> <h3>Acknowledgements:</h3> <b>NIL.</b> <h3>Disclosure of Interests:</h3> <b>None declared.</b>