LAMDA: a lupus arthritis score built against ultrasound synovitis

Design

Prospective multicentre derivation cohort with external validation

Population

133 patients with lupus arthritis (derivation); 44 (validation)

Primary outcome

Construct validity, responsiveness and thresholds of a composite score

Effect

Responsiveness effect size 0.40 after glucocorticoid (P < 0.0001)

This Lancet Rheumatology cohort study, published on 2 September, derived a composite activity score for lupus arthritis from 133 patients at seven English hospitals, using hand and wrist ultrasound as the reference. The final LAMDA score combines four items: swollen joint count, ESR, physician musculoskeletal activity and patient musculoskeletal pain. A 28-joint count could replace the 66-joint count.

LAMDA correlated with ultrasound, conventional activity measures and patient-reported outcomes, and changed after glucocorticoid treatment (effect size 0.40). In an external cohort of 44 patients, its proposed thresholds discriminated treatment decisions and patient-acceptable symptoms better than swollen joint counts alone.

Lupus arthritis is often under- or over-estimated clinically, and trials have used insensitive measures. LAMDA may give clinics a practical score using data they already collect.

• Record swollen joint count, ESR, physician global and patient pain at lupus arthritis visits.
• A 28-joint count may be enough for scoring.
• Consider ultrasound when clinical assessment of lupus synovitis is uncertain.
• Watch for validation in larger trials before adopting thresholds.

Why it matters

Lupus arthritis trials may have failed partly because they measured the joints badly.

Don't overread it

Thresholds are provisional; derivation and validation cohorts were small.

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