RESUMEN
Epidermolysis bullosa (EB) is a rare disease characterised by skin fragility and a wide variety of symptoms. The Quality of Life in Epidermolysis Bullosa (QOLEB) score is an English 17-item EB-specific validated measurement tool with two dimensions: functioning and emotions. The aim of this cross-sectional study was to develop and validate a culturally adapted German QOLEB. The following steps were carried out: translation, expert evaluation, back translation, linguistic and cultural adaptation, sample-based psychometric testing and evaluation. Data analysis was performed with n = 46 patients across all EB types. The reliability and internal consistency of the translated German QOLEB were excellent (α = 0.901). Regarding convergent validity, the QOLEB correlated highly with the iscorEB (r = 0.879; p < 0.001). Structural similarity with the English original version was confirmed through exploratory factor analysis. In conclusion, the German QOLEB demonstrates internal reliability and construct validity and is suitable to assess the quality of life in German-speaking EB patients.
RESUMEN
BACKGROUND: In contrast to clinical diagnosis via external examination, patient-related outcome measures allow to access the patients' internal perception. Particularly, in the case of epidermolysis bullosa (EB), a rare disease characterized by a wide variety of symptoms and individual courses of disease, it is central to integrate the patient's perspective into diagnostic processes. OBJECTIVES: The Instrument for Scoring Clinical Outcome of Research for EB (iscorEB) is an EB-specific measurement tool, combining a clinician score (iscorEB-c) and a patient questionnaire (iscorEB-p). The aim of this study is to establish the iscorEB-p as an independent patient-related outcome measure tool by exploring its psychometric properties. METHODS: The following steps were performed on data collected via a multinational online cross-sectional study: sample-based psychometric testing and evaluation. RESULTS: Data analysis was performed with n=95 participants across all EB types. The reliability and internal consistency of the iscorEB-p was excellent (α=0.90). A principal component analysis with a varimax rotation resulted in a two-factor solution, explaining 55.6% of the total variance, with the distinct factors "everyday life functioning" and "specific EB symptoms". Convergent validity was shown by high correlations to the SWLS (r=-0.52, p<0.001), the QOLEB (r=0.72, p<0.001) and EB-BoD (r=-0.73, p<0.001). CONCLUSIONS: In conclusion, the iscorEB-p is a reliable and valid instrument to assess the patient-reported view on the health status of EB patients.
