Pulmonary outcome differences in U.S. and French cystic fibrosis cohorts diagnosed through newborn screening

BackgroundA comparison of the longitudinal progression of lung disease in cystic fibrosis patients identified through newborn screening (NBS) in cohorts located in two different countries has never been performed and was the primary objective of this study.MethodsThe study included 56 patients in Brittany diagnosed through NBS between 1989 and 1994 and 69 similar patients in Wisconsin between 1985 and 1994. The onset and progression of lung disease was radiographically quantified using the Wisconsin Chest X-ray (WCXR) scoring system. A single pediatric pulmonologist blinded to all identifiers scored the films.ResultsGeneralized estimating equation analyses adjusted for age, genotype, sex, pancreatic insufficiency, and meconium ileus showed worse WCXR scores in Brittany patients compared to Wisconsin patients (average score difference = 4.48; p < 0.001). Percent predicted FEV1 was also worse among Brittany patients (p < 0.001).ConclusionsThe finding of milder radiographically-quantified lung disease using the WCXR scoring system, as well as better FEV1 values, may be explained by variations in nutrition, environmental exposures, or healthcare delivery.