Primary ciliary dyskinesia: First health-related quality-of-life measures for pediatric patients

Rationale: Primary ciliary dyskinesia (PCD) is a rare disease. There are no available data on disease-specific pediatric patient-reported outcomes. Objectives: Our objective was to create developmentally appropriate, health-related quality-of-life questionnaires (QOL-PCD) for children (6-12 yr) and adolescents (13-17 yr) with PCD and a parent proxy measure. Methods: The QOL-PCD was developed using a cross-cultural protocoldriven approach satisfying both North American and European drug regulatory agency guidelines. A conceptual framework was generated by literature review, focus groups (expert clinicians and patients/parents), and open-ended interviews with children, adolescents, and parents of patients with PCD.Werecruited participants frominternational research consortiums, PCD clinics, and patient advocacy groups, aiming for representation of a wide spectrum of disease severity, sociodemographic status, and ethnicity. Qualitative interviews were conducted by trained and experienced research assistants and psychologists. Transcripts were content-analyzed with Atlas.ti/ NVivo to assess saturation of content. A self-completed item relevance survey was administered to E.U. participants. Qualitative and quantitative data were used to construct draft instruments. Questionnaires were further refined after cognitive interviews. Measurements and Main Results: Focus groups (n = 62 experts; n = 20 patients/parents) and open-ended interviews with patients/parents (n = 69; 34 males; age at diagnosis, 0-15 yr; FEV1, 58-118% predicted) revealed a wide spectrum of issues unique to this population. Content analysis of transcripts identified the following domains, depending on age: Respiratory Symptoms, Physical Functioning, Emotional Functioning, Treatment Burden, Ears and Hearing, Sinus Symptoms, Social Functioning, Role Functioning, Vitality, Health Perceptions, SchoolFunctioning, andEating andWeight.Various items were retained in questionnaires, based on age and role of respondent: 37, 43, and 41 items for children, adolescents, and parent proxy, respectively.The item relevance survey (n = 57) yielded results similar to those of open-ended interviews. Cognitive testing (n = 47; 20males; age at diagnosis, 0-11 yr; FEV1, 49-124% predicted) confirmed that items and response choices were clear and understood by respondents, and that all relevant items were included. Conclusions: The QOL-PCD measures, developed using rigorous, protocoldriven methods and international collaborations, have demonstrated content validity and cross-cultural equivalence for implementation in English-speaking populations. Psychometric testing is underway to determine their measurement properties for evaluating clinical interventions and informing quality of care.