LBA:01:17 ASSESSLE: a novel disease activity tool for the assessment of systemic lupus erythematosus

Objectives To develop and validate a user-friendly composite tool (ASSESSLE) for monitoring SLE disease activity that integrates physician assessment with patient-reported outcomes, addressing limitations of existing indices in sensitivity, feasibility, and patient perspective capture.Methods The physician component includes seven visual analogue scale (VAS) domains and serologic dynamics. Reliability and validity were evaluated in a pilot paper-case study (4 cases, 5 raters) and in a prospective cohort (45 patients, 127 visits), with comparisons to BILAG, SLEDAI, and LFA-REAL. The PRO component comprises four VAS items and was compared with the SF-36 across repeated visits. Diagnostic performance for detecting clinical improvement or worsening was assessed using area under the ROC curve (AUC) analysis based on physician intent-to-treat (ITT). SLE Responder Index-4 (SRI-4) was applied and compared with the ASSESSLE physician component to assess discriminatory ability relative to physician-determined treatment modification. Predictive validity of the PRO for disease flares was evaluated using an ITT framework.Results In the pilot study, the physician component showed excellent inter-rater reliability (ICC 0.75–0.95) and good convergent validity with BILAG, SLEDAI, and LFA-REAL (r = 0.48–0.94). In the prospective cohort, ASSESSLE correlated with BILAG (r = 0.71) and SLEDAI (r = 0.69), explained up to 85% of BILAG variance, and showed greater sensitivity to change than SLEDAI (r = 0.62 vs. 0.59), with simplicity comparable to LFA-REAL. Among visits with clinical improvement or worsening (n = 72), ASSESSLE demonstrated higher diagnostic performance than BILAG, SLEDAI, and LFA (AUC 0.72 vs. 0.708, 0.693, and 0.659, respectively). Compared with SRI-4, the ASSESSLE physician component demonstrated superior ability to identify responders based on physician-driven treatment modification (73% vs. 52%). The PRO correlated strongly with SF-36 (r = 0.85, p < 0.0001). A PRO score below 6.8 ( scale 0-10) predicted flares with 80% specificity and 81.6% sensitivity.Conclusions ASSESSLE is a reliable, responsive, and pragmatic composite measure that captures clinically meaningful changes in SLE activity and performs favorably relative to established indices. Its concise PRO component adds patient-centered value and may assist flare prediction, supporting ASSESSLE’s suitability for routine clinical practice and research.