A NEWLY derived composite score has been shown to improve the assessment of lupus arthritis, addressing a long-standing gap in disease activity measurement for systemic lupus erythematosus trials.
Existing lupus arthritis measures have relied on simplified joint counts that do not adequately capture disease severity or meaningful change. Tender joint counts lack specificity for ultrasound-detected synovitis, and swollen joint counts correlate weakly with patient-reported outcomes, while tools borrowed from rheumatoid arthritis remain poorly suited to a multiorgan disease. No validated instrument has previously captured the full impact of lupus arthritis, prompting researchers to derive the Lupus Arthritis and Musculoskeletal Disease Activity (LAMDA) score.
In this cohort study, LAMDA was derived from baseline data in the prospective, multicentre USEFUL study of participants with systemic lupus erythematosus receiving intramuscular glucocorticoid therapy for lupus arthritis across seven English hospitals. Penalised quantile regression of ultrasound synovitis scores on core arthritis variables, including joint counts, erythrocyte sedimentation rate, and patient and physician visual analogue scales, derived the score. Construct validity, known groups validity, and responsiveness were assessed, and thresholds for trial entry, minimal disease activity, and clinically important improvement were set using receiver operating characteristic analysis. A separate external validation cohort was recruited from Leeds.
The USEFUL study included 133 participants recruited between October 2016 and December 2018 (mean age 47.0 years, IQR 35.0 to 55.0; 95% female; 62% White). The final LAMDA score retained four variables: swollen joint count, erythrocyte sedimentation rate, physician musculoskeletal disease activity, and participant musculoskeletal pain. LAMDA correlated well with conventional disease activity measures, ultrasound findings, and patient-reported outcomes, and showed a medium to large treatment effect after glucocorticoid therapy (effect size 0.40; p<0.0001). The external cohort of 44 participants (median age 48.5 years, IQR 39.0 to 56.0; 86% female) supported these findings, with LAMDA thresholds outperforming swollen joint counts in discriminating treatment intention and symptom state.
LAMDA has emerged as a novel, ultrasound-derived tool with the potential to improve assessment of lupus arthritis in trials and everyday practice. Further validation is underway in large multinational trials, and LAMDA has already been incorporated into multiple phase 3 trials and selected for the arthritis domain of the international Treatment Response Measure-SLE initiative.
Reference
Wood S et al. Derivation, validation, and proposed thresholds of the Lupus Arthritis and Musculoskeletal Disease Activity (LAMDA) instrument: a cohort study. Lancet Rheumatol. 2026;DOI:10.1016/S2665-9913(26)00208-0.
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