ABSTRACT
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.
ABSTRACT
BACKGROUND: There is a lack of validated standardized outcome measures for epidermolysis bullosa (EB) that can separate activity from damage. OBJECTIVE: We sought to develop and validate an instrument for inherited EB of all ages and subtypes, the EB Disease Activity and Scarring Index (EBDASI), which scores activity responsive to therapy separately from scarring. METHODS: The EBDASI was validated by comparing its reliability and validity against the Birmingham EB Severity (BEBS) score (partially validated with activity mixed with scarring), using the Physician Global Assessment (PGA) scale as a reference measurement. Sixteen patients with EB (7 EB simplex, 5 dominant dystrophic EB [DDEB], 2 junctional EB, and 2 recessive dystrophic EB) were assessed by 5 EB experts using the EBDASI, BEBS, and PGA, and data from 9 additional patients assessed on an ad hoc basis during routine patient clinic were also included. RESULTS: For interrater reliability, the overall total score intraclass correlation coefficients (95% confidence intervals) were: EBDASI 0.964 (0.929-0.986), BEBS 0.852 (0.730-0.937), and PGA 0.873 (0.765-0.946). For intrarater reliability, the intraclass correlation coefficients were: EBDASI 0.994 (0.976-0.998), BEBS 0.926 (0.748-0.981), and PGA 0.932 (0.764-0.982). The EBDASI had a higher correlation with PGA (ρ = 0.871) than BEBS with PGA (ρ = 0.852). Intraclass correlation coefficients scatterplots showed the EBDASI was better at distinguishing milder forms of EB, with better correlations at higher severity scores than the BEBS. LIMITATIONS: A limited number of patients were recruited for this study. An independent study will be required to demonstrate the responsiveness of the EBDASI. CONCLUSION: The EBDASI demonstrated excellent reliability and validity, as compared with 2 other outcome measures.