A comparison study of outcome measures for epidermolysis bullosa: Epidermolysis Bullosa Disease Activity and Scarring Index (EBDASI) and the Instrument for Scoring Clinical Outcomes of Research for Epidermolysis Bullosa (iscorEB)

Background The success of clinical trials in Epidermolysis Bullosa (EB) is dependent upon the availability of a valid and reliable scoring tool that can accurately assess and monitor disease severity. The Epidermolysis Bullosa Disease Activity and Scarring Index (EBDASI) and Instrument for Scoring Clinical Outcomes of Research for Epidermolysis Bullosa (iscorEB) were independently developed and validated against the Birmingham Epidermolysis Bullosa Severity Score but have never been directly compared. Objective To compare the reliability, convergent validity, and discriminant validity of the EBDASI and iscorEB scoring tools. Methods An observational cohort study was conducted in 15 patients with EB. Each patient was evaluated using the EBDASI and iscorEB-clinician scoring tools by 6 dermatologists with expertise in EB. Quality of life was assessed using the iscorEB-patient and Quality of Life in EB measures. Results The intraclass correlation coefficients for interrater reliability were 0.942 for the EBDASI and 0.852 for the iscorEB-clinician. The intraclass correlation coefficients for intrarater reliability was 0.99 for both scores. The two tools demonstrated strong convergent validity with each other. Conclusion Both scoring tools demonstrate excellent reliability. The EBDASI appears to better discriminate between EB types and disease severities.