Background/Purpose: .   

In order to more accurately capture disease activity and damage in juvenile Localized Scleroderma (jLS) and to develop an accepted outcome measure for treatment protocols, an LS-focused Childhood Arthritis and Rheumatology Research Alliance subgroup developed clinical disease activity and damage measures.  The objective of this abstract is to discuss the assessment of the reliability and validity of the LS Damage Score in jLS.  The LS Damage Score includes four domains (dermal atrophy, subcutaneous atrophy, dyspigmentation {hyper/hypo pigmentation}, and skin thickness of lesion center) which are scored for all affected sites.

Methods:

Thirteen pediatric rheumatologists and a dermatologist attended a 2-day workshop meeting to review LS clinical measures.  Raters ranked 13 jLS patients on damage domains at 2 time points.  Patients were presented to raters in random order in efforts to reduce recall bias.  For each patient, raters were told which anatomic sites to assess (1-2/patient).  Physicians also completed Physician Global Assessment of Disease for Activity and Damage (PGA-A; PGA-D).  To examine construct validity, we hypothesized that the LS Damage Score would have a moderate correlation to PGA-D and a low correlation to PGA-A.  Spearman’s rho was calculated to quantify the relationship with clinical parameters, and intraclass correlation coefficients (ICC) were examined to determine inter/intra rater reliability (0.20-0.39 low, 0.40-0.59 moderate, 0.60-0.79 high). 

Results:

Median age of LS patients was 13 years (IQR = 9.5-17) and the most common subtype was linear scleroderma (4 limb, 4 head).  Mean LS Damage Scores ranged from 3.96 to 16.46 (max score 24); PGA-D ranged from 14.54 to 53.48 (max score 100).  There was a low correlation between the LS Damage Score and both PGA-D and PGA-A (ρ = .11, ρ = .14).  Raters demonstrated moderate/high inter and intra-rater reliability for the LS Damage score, and low/moderate inter and intra-rater reliability for PGA-D. Among the domains, hypopigmentation showed the lowest inter-rater reliability.(Table1) 

Table 1: Inter-rater and intra-rater reliability of LS Damage score

Conclusion:   

The LS Damage Score had moderate-high reliability between and among raters, with hyperpigmentation, skin thickness center, and dermal atrophy contributing most to the total score.  Overall, the inter-rater agreement of damage components increased in session 2. The PGA-D performed well within the rater’s repeat assessment, but poorly in regards to inter-rater reliability. The poor correlation between PGA-D and LS Damage Score may reflect MD inclusion of extracutaneous manifestations (ECM), such as facial disfigurement.   In post-hoc analysis, when patients with facial linear scleroderma were removed, the correlations of PGA-D with LS Damage Score increased (ρ = .317).  Additional studies are needed to fully evaluate this measure.