Using the Localized Scleroderma Cutaneous Assessment Tool (LoSCAT) to classify morphoea by severity and identify clinically significant change

Background Validated scoring measures in morphoea can facilitate clinical trials. Objectives To ascertain the clinical significance of scores on the Localized Scleroderma Cutaneous Assessment Tool (LoSCAT) and identify the change in scores correlated with clinically meaningful change. Methods A prospective study of 120 participants from the Morphea in Adults and Children (MAC) cohort was undertaken. Physician's subjective assessments of severity and of improvement were completed at each visit. Receiver operating characteristic analysis determined LoSCAT scores corresponding with mild, moderate and severe disease, and absolute and percentage changes in scores corresponding with improved or worsened disease activity or damage. Results Mild, moderate and severe activity corresponded with LoSCAT activity index (LoSAI) scores of 0-4, 5-12 and 13 and over, and with Physician's Global Assessment of activity (PGA-A) scores of 0-10, 11-30 and 31 and over. Mild, moderate and severe damage corresponded with LoSCAT damage index (LoSDI) scores of 0-10, 11-15 and 16 and over, and with PGA of damage (PGA-D) scores of 0-18, 19-30 and 31 and over. Improved activity was best indicated by LoSAI decrease of at least 2 points or 27 center dot 5%, or PGA-A decrease of at least 6 points. Improved damage was best indicated by LoSDI score decrease of at least 2 points. Worsening activity was best indicated by LoSAI increase of at least 2 points or 19 center dot 5%, or PGA-A increase of at least 4 points. Worsening damage was best indicated by LoSDI increase of at least 25 center dot 5%. Conclusions The LoSCAT can be used to classify patients with morphoea by disease severity, and identify clinically significant improvement in activity.