Background/Purpose: The Cutaneous Lupus Disease Area and Severity Index (CLASI) can quantify disease activity and damage in Cutaneous Lupus Erythematosus (CLE). Classification of CLASI scores provides standardized clinical context for patients and providers. A prior study used a small patient cohort to classify CLASI activity (CLASI-A) scores into mild, moderate and severe categories, but was limited by small sample size.¹ The objectives of the present study were to classify both CLASI-A and CLASI damage (CLASI-D) scores into mild, moderate, and severe categories using a large, heterogeneous cohort of CLE patients, and determine risk factors for different categories of activity and damage.

Methods: This was a single-center, cross-sectional study involving patients seen in the outpatient dermatology clinics at University of Texas Southwestern and Parkland Health and Hospital System from April 2009 to January 2020. Table 1 shows demographic and clinical features of participants. Skin severity measurements including CLASI and Physicians’ Global Assessment (PGA) of Activity and Damage were scored for all patients. The anchoring outcome measure was the PGA-A and PGA-D, which classified patients into mild, moderate, and severe categories for subsequent analysis with CLASI scores. Severity strata were evaluated using receiver operating characteristics (ROC) curves. Skindex-29+3 scores were collected to evaluate patient quality of life.

Results: 270 patients with CLE (Table 1) met recruitment criteria. CLASI-A scores of 0-6, 7-14, and 15-70 corresponded to mild, moderate, and severe disease activity. These performed better than previously published strata¹ by sensitivity, specificity, and percent correctly classified (Table 2). CLASI-D scores of 0-5, 6-16, and 17-56 corresponded to mild, moderate, and severe disease damage. Patients had significantly more impaired quality of life with more severe categories of both activity and damage (p< 0.0001). About half (55%) of patients had matching disease activity and damage categories, with the other half having discrepant categories. Smoking (p=0.002), race (p< 0.0001), CLE subtype (p< 0.0001), and disease duration (p=0.02) were factors that were significantly different amongst the groups of activity and damage (Figure 1). Black race, chronic CLE, and longer disease duration were associated with disease damage disproportionately worse than disease activity. Smoking was associated with worsening severity of both activity and damage.

Conclusion: CLASI-A and CLASI-D scores can be classified into mild, moderate, and severe categories with high specificity and sensitivity using a large, diverse cohort. This will allow providers to have greater context of disease severity using CLASI scores for prognostic, clinical, and research use. Future studies across multiple cohorts will help validate these ranges.

Reference: 1. Klein R, Moghadam-Kia S, LoMonico J et al. Development of the CLASI as a tool to measure disease severity and responsiveness to therapy in cutaneous lupus erythematosus. Arch Dermatol 2011; 147:203-208. doi:10.1001/archdermatol.2010.435

Table 1: Patient Clinical and Demographic Characteristics (N&#3f270)

Table 2: Percent sensitivity, specificity, and correctly classified for CLASI category ranges.

Figure 1: Characteristics associated with different categories of activity and damage.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/classification-of-disease-activity-and-damage-in-cutaneous-lupus/