Background/Purpose:   Childhood-onset systemic lupus erythematosus (cSLE) is a chronic autoimmune disease, which can affect any organ system. cSLE is associated with significant morbidity, including diverse types of disease-related organ damage: up to 58% of children have apparent damage at 5 years after diagnosis. The Systemic Lupus Collaborating Clinics-Damage Index (SDI) is the only widely-used damage measure in patients with SLE (and cSLE), but was designed to list extant types of damage, not quantify severity. We sought to determine how this “listing” approach compared to a physician global assessment of disease-related damage in an international registry of cSLE patients.

Methods: The PRINTO (Pediatric Rheumatology International Trials Organization) cSLE registry includes longitudinal follow-up (mean approximately 3 years) of patients meeting revised American College of Rheumatology criteria for classification of SLE. Data from 557 patients, with a total of 1820 visits, was available for review. Data included SDI item and total scores, as well as a physician visual analog scale rating damage from 0 to 10. First, frequency of SDI summary scores was determined. The total SDI score and physician global rating of disease damage were then examined for correlation via Spearman rank-order testing. Finally, a mixed-effect model was used to determine the association of individual items with the physician damage global assessment.

Results: Out of 1820 visits, 1268 visits were assigned a SDI score of zero, while 552 (30.3%) had a non-zero score. Of non-zero scores, 331 visits received a score of one, 116 a score of two, 48 a score of three, 18 each a score of four or five, and 11 a score of six. A further 10 visits were assigned a SDI score of greater than 6. Spearman correlation of non-zero SDI scores with damage VAS was moderate at 0.496 (p value <0.0001). When visits with a SDI score of zero were included, the correlation coefficient was strong at 0.71 (p value <0.0001). Interestingly, of visits with a SDI score of zero (n=1268) 23.7% (n=301) were assigned a physician damage global greater than zero. Mixed effect analysis revealed that only 4 of the 41 SDI items were significantly associated with the physician damage global rating (Pulmonary Fibrosis, Shrinking Lung Syndrome, Chronic Pericarditis, Extensive Cutaneous Scar).

Conclusion: Our analysis revealed that a significant number of cSLE patients were found to have disease-related damage, even within the relatively limited follow-up period. It is also interesting to note the significant discrepancy between SDI scores of zero with non-zero physician global assessments, which could suggest either misunderstanding of the scale by raters, or damage items not captured by the SDI. The moderate correlation between non-zero SLICC-DI scores and the physician damage assessment suggests the need for a new or modified scale to specifically address damage severity. Finally, the lack of an association between the great majority of damage items and the physician damage assessment implies that item weightings alone would be insufficient to improve capture of damage severity.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/comparison-of-the-systemic-lupus-collaborating-clinics-damage-index-score-with-a-physician-global-assessment-of-damage-in-an-international-cohort-of-patients-with-childhood-onset-systemic-lupus/