Psychometric evaluation of the Cystic Fibrosis Questionnaire-Revised in a national sample.

Purpose: The psychometric properties of a health-related quality of life (HRQOL) instrument, the Cystic Fibrosis Questionnaire-Revised (CFQ-R), were evaluated in a national sample of patients with cystic fibrosis (CF).

Methods: The Epidemiologic Study of CF is a national, multicenter, longitudinal cohort study containing CFQ-R and health outcomes data. Developmentally appropriate versions of the CFQ-R were available from 7,330 patients aged 6-70 years and a proxy version from 2,728 parents of school-age children. The CFQ-R was completed during a "stable" or "sick" visit before recording health outcomes such as weight, lung function, and pulmonary exacerbations.

Results: There were few floor and ceiling effects and strong internal consistency (Cronbach alpha ≥0.70) for most scales. The CFQ-R consistently discriminated between patients seen for sick-versus-well visits, and among stages of disease severity based on lung function. As predicted, women with CF reported worse HRQOL than men on scales not related to body image and weight. Strong parent-child agreement was found on scales measuring observable behaviors (respiratory symptoms). Convergence between CFQ-R scales and health outcomes provided evidence of construct validity.

Conclusions: The CFQ-R demonstrated robust psychometric properties and consistent associations with health outcomes in a large national sample.