Objective: Existing methods for grading lupus flares or improvement require definition-based thresholds as increments of change. Visual analogue scales (VAS) allow rapid, continuous scaling of disease severity. We analysed the performance of the SELENA SLEDAI Physician's Global Assessment (SSPGA) and the Lupus Foundation of America-Rapid Evaluation of Activity in Lupus (LFA-REAL) as measures of improvement or worsening in SLE.
Methods: We evaluated the agreement between prospectively collected measures of lupus disease activity [SLE Disease Activity Index (SLEDAI), British Isles Lupus Assessment Group Index 2004 (BILAG 2004), Cutaneous Lupus Area and Severity Index (CLASI), SSPGA and LFA-REAL] and response [(SLE Responder Index (SRI)-4 and BILAG-Based Combined Lupus Assessment (BICLA)] in a clinical trial.
Results: Fifty patients (47 females, mean age 45 (±11.6) years) were assessed at 528 consecutive visits (average 10.6 (±4.1) visits/patient). Changes in disease activity compared with baseline were examined in 478 visit pairs. SSPGA and LFA-REAL correlated with each other (r=0.936), and with SLEDAI and BILAG (SSPGA: r=0.742 (SLEDAI), r=0.776 (BILAG); LFA-REAL: r=0.778 (SLEDAI), r=0.813 (BILAG); all p<0.0001). Changes (∆) in SSPGA and LFA-REAL compared with screening correlated with each other (r=0.857) and with changes in SLEDAI and BILAG (∆SSPGA: r=0.678 (∆SLEDAI), r=0.624 (∆BILAG); ∆LFA-REAL: r=0.686 (∆SLEDAI) and 0.700 (∆BILAG); all p<0.0001). Changes in SSPGA and LFA-REAL strongly correlated with SRI-4 and BICLA by receiver operating characteristic analysis (p<0.0001 for all). Additionally, LFA-REAL correlated to individual BILAG organ scores (musculoskeletal: r=0.842, mucocutaneous: r=0.826 (p<0.0001 for both)).
Conclusion: SSPGA and LFA-REAL are reliable surrogates of common SLE trial end points and could be used as continuous or dichotomous response measures. Additionally, LFA-REAL can provide individualised scoring at the symptom or organ level.
Trial registration number: NCT02270957.
Keywords: disease activity; outcomes research; systemic lupus Erythematosus.
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