Development of the Cystic Fibrosis Questionnaire (CFQ) for assessing quality of life in pediatric and adult patients

To assess the impact of cystic fibrosis (CF) and treatment on quality of life (QOL) from childhood throughout adult age, two versions of the Cystic Fibrosis Questionnaire (CFQ), were developed and validated in France: the CFQ 14+ for teenagers and adults, the CFQ Child P, a parent-proxy evaluation for children aged 8–13. They include three modules for assessing QOL, symptoms and health perception. Nine QOL dimensions were identified: physical functioning, energy/well-being, emotions, social limitations, role, embarrassment, body image, eating disturbances and treatment burden. Items were derived from 33 interviews with patients and parents. Item reduction and assessment of internal consistency, convergent and discriminant validity were based on a large cross-sectional survey among 393 patients and parents. A second study was conducted among 124 patients and 85 parents to test reproducibility and responsiveness, confirm the subscale structure and assess scalar properties using Rasch analysis. All psychometric properties were successfully demonstrated and both the CFQ 14+ and the CFQ Child P French questionnaires are now well validated. German and Spanish validated adaptations are available, an English validation is in progress. Conclusion: The CFQ 14+ and CFQ Child P are well validated, multilingual measures which allow QoL assessment in children, teenagers and adults with CF.