Development and Validation of the eHealth Literacy and Use Scale (eHLUS) to Measure Medical App Literacy.

Abstract The digital transformation in healthcare has significantly driven the integration of medical apps into patient care. The proliferation of medical apps requires a comprehensive understanding and assessment of users' eHealth literacy. Traditional eHealth literacy assessment tools often overlook the direct access to evidence-based information that medical apps provide. To close this gap, we developed and validated the eHealth Literacy and Use Scale (eHLUS), a German-language instrument tailored to the specific requirements of medical app use, such as integration into everyday life and self-efficacy. The eHLUS exhibited robust psychometric properties when evaluated with 121 cases. The evaluation results of the scale, along with the eleven expert interviews conducted as part of the scale development, underscore both the necessity and feasibility of the scale. The eHLUS captures eHealth literacy and its associated determinants in the context of medical app use, thus contributing to optimizing patient care.