Forward-backward translation and content validity study of the German version of the Patient-Reported Apnea Questionnaire

Background Health-related quality of life (HRQOL) assessment is an important component of chronic disease management, providing insights beyond clinical parameters. In obstructive sleep apnea (OSA), no comprehensive German-language patient-reported outcome measure (PROM) is currently available for routine clinical use. This study aims to adapt the Patient-Reported Apnea Questionnaire (PRAQ), a validated OSA-specific HRQOL instrument, for German-speaking patients. Methodology The German adaptation of the PRAQ followed a forward-backward translation process involving three translators. After harmonization, content validity was assessed through cognitive interviews with 20 OSA patients and an online survey among 14 sleep medicine experts. Feedback from both groups was incorporated into the final version of the questionnaire. Results The translation and adaptation process was conducted between April 2025 and March 2026. Two forward translations, one back-translation, and a final harmonization were performed. Patients identified issues mainly related to item relevance, conceptual overlap and response formats in the domains of daily activity, emotions and social interactions. Experts confirmed overall good comprehensibility but highlighted some concerns regarding item relevance and response scales. Based on patient and expert feedback, eight modifications were implemented, including clarifications of OSA-related terms, response options, and specific item wording, resulting in the final German PRAQ version. Conclusion The German version of the PRAQ demonstrates decent content validity and comprehensibility, while reflecting the heterogeneous experiences of patients with OSA. Although some items were considered less relevant by certain patients, no essential domains were identified as missing. The study was approved by the ethics committee of the ​ University of Duisburg-Essen (25-12560-BO), and all participants provided written informed consent.