Background/Purpose: Systemic lupus erythematosus (SLE) is a heterogeneous, waxing and waning, multisystem autoimmune disease. The complexity and clinical unpredictability of SLE challenge the assessment of disease activity over time, especially in every day clinical practice. Multiple clinical disease monitoring instruments have been developed, however they are limited in ability to detect change in disease activity over time or too cumbersome to be utilized in daily practice. The aim of the study is to construct a new disease activity score which will simplify and improve disease activity assessment in daily practice, and possibly serve as a better tool for clinical studies.

Methods: The new instrument for the assessment of SLE activity is comprised of 6 visual analogue scales (VAS), which separately address the physician’s global assessment and 5 organ systems including: mucocutaneous, musculoskeletal, cardiorespiratory, renal and neuropsychiatric systems. Changes in blood counts, serology, and medications are recorded. The patient’s own assessment, as well as treatment changes will be included in the final score. In order to assess the reliability and validity of the new score, as well as the score’s sensitivity to change in disease activity, 4 paper cases, including 2 visits for each case, were constructed. Each of the visits was scored by 5 experienced rheumatologists who were not involved in the construction of the new score, using 3 validated scoring instruments: BILAG, SLEDAI, LFA-REAL, and our proposed score. The order of the instruments utilized for each scored visit and the order of patients scored by each physician were randomized.

Results: The inter-rater reliability (i.e. agreement between physicians) of the new score was good for all systems represented in the paper cases, both for single visit scores and for the change in disease activity between 2 consecutive visits (ICC (2,1) range 0.75-0.95), except for a borderline value for changes in disease activity in the renal system (0.59). The inter-rater reliability values of the new score were comparable with those of the BILAG and the LFA-REAL scoring systems. The construct (convergent) validity of the new score, as evaluated by correlation with the other 3 validated scoring instruments was good for single visit scores (Spearman correlation coefficients range 0.48-0.94). Correlation of our proposed score with the BILAG score, regarding changes in disease activity, was good when scoring the mucocutaneous, musculoskeletal and cardiorespiratory systems (0.66, 0.75, 0.83, respectively) but was poor when scoring the renal system (0.11).

Conclusion: This paper case evaluation of the new disease activity score suggests a promising and simple tool, with overall good reliability and construct validity. Further studies are ongoing to evaluate a greater diversity of real-life patients with SLE. Further psychometric evaluation is needed to refine the score and to incorporate laboratory and medication data and patient assessment.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/systemic-lupus-erythematosus-a-pilot-study-of-a-new-disease-activity-score/