Capturing the Range of Disease Involvement in Localized Scleroderma: The Localized Scleroderma Total Severity Scale.

Area of Science:

• Rheumatology
• Pediatric Autoimmune Diseases
• Clinical Outcome Measures

Background:

• Juvenile localized scleroderma (jLS) is a chronic autoimmune condition with significant potential for long-term functional impairment.
• Current treatment improvements have not fully addressed the >25% of patients experiencing functional deficits.
• There is a need for a comprehensive tool to assess overall disease severity in jLS.

Purpose of the Study:

• To develop and validate the Localized scleroderma Total Severity Scale (LoTSS) as a comprehensive measure of overall disease severity in juvenile localized scleroderma.
• To create a tool that assesses cutaneous and extracutaneous manifestations of jLS.
• To establish a reliable and valid instrument for use in clinical practice and research.

Main Methods:

• LoTSS was developed through a consensus process including literature review, surveys, case vignettes, and multicriteria decision analysis.
• Feasibility was assessed in large research networks, and construct validity was evaluated using physician assessments and inter-rater reliability with case vignettes.
• The scale was further validated in a prospective cohort of patients initiating treatment.

Main Results:

• LoTSS is organized into modules for skin, extracutaneous, and craniofacial manifestations.
• The scale demonstrated strong construct validity, correlating positively with Physician Global Assessment of severity and damage, and showed responsiveness.
• Moderate-to-excellent inter-rater reliability was achieved, and LoTSS effectively discriminated between patient subsets with higher scores in those with greater disease burden.

Conclusions:

• The developed LoTSS is a reliable, valid, and responsive measure for assessing both cutaneous and extracutaneous severity in jLS.
• LoTSS is the first instrument to comprehensively score major extracutaneous manifestations in localized scleroderma.
• The LoTSS has the potential to improve patient assessment and management, and to facilitate outcome evaluation in clinical trials for jLS.