title: Cystic fibrosis diagnosed after 2 months of age leads to worse outcomes and requires more therapy.
abstract: OBJECTIVE
  Newborn screening for cystic fibrosis remains controversial because improved pulmonary function has not been established. Studies to date have not accounted for differences in treatments delivered to clinically diagnosed children and newborn-screened controls. Here, we compare outcomes and treatment of patients clinically diagnosed within the newborn-screening reporting window (early-clinically diagnosed), those presenting after this period (late-clinically diagnosed), and patients diagnosed by newborn screening.
  
  
  METHODS
  In a cross-sectional analysis of cohorts retrospectively ascertained, patients who were homozygous deltaF508 with cystic fibrosis, attending specialist cystic fibrosis centers, and 1 to 10 years of age between 2000 and 2002 were identified from the United Kingdom Cystic Fibrosis Database and stratified into newborn-screened, early-clinically diagnosed, or late-clinically diagnosed cohorts. Two analyses were performed: (1) after restricting to the most recent year of data collection, early-clinically diagnosed and late-clinically diagnosed cohorts were matched to newborn-screened patients by patient age and year of data collection (133 patients per cohort were identified); and (2) for all years of data collection, annual sets of data for early-clinically diagnosed and late-clinically diagnosed patients were matched to newborn-screened patients by patient age and year of data collection (291 data sets per cohort were identified). Median height and weight z scores, proportion of patients with height and weight <10th percentile, prevalence of chronic Pseudomonas aeruginosa infection, Shwachman-Kulczyki morbidity scores, percent predicted forced expiratory volume in 1 second, and numbers of long-term therapies were compared.
  
  
  RESULTS
  In both analyses, newborn screening was associated with higher height z score, higher Shwachman-Kulczyki score, lower likelihood of height <10th percentile, and fewer long-term therapies compared with late-clinically diagnosed patients. No other differences were found.
  
  
  CONCLUSIONS
  Newborn screening was associated with improved growth, reduced morbidity, and reduced therapy, yet generated equivalent pulmonary outcome compared with late clinical diagnosis, suggesting that newborn screening may slow cystic fibrosis lung disease progression.
authors.affiliation: United Kingdom Cystic Fibrosis Database, Division of Maternal and Child Health Sciences, Ninewells Hospital and Medical School, University of Dundee, Dundee, Scotland, United Kingdom. e.sims@uea.ac.uk
authors.forename: Erika J
authors.initials: EJ
authors.lastname: Sims
authors.forename: Allan
authors.initials: A
authors.lastname: Clark
authors.forename: Jonathan
authors.initials: J
authors.lastname: McCormick
authors.forename: Gita
authors.initials: G
authors.lastname: Mehta
authors.forename: Gary
authors.initials: G
authors.lastname: Connett
authors.forename: Anil
authors.initials: A
authors.lastname: Mehta
mesh_terms: D000367:Age Factors; D001827:Body Height; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003550:Cystic Fibrosis / Q000150:complications / Q000175:diagnosis* / Q000188:drug therapy / Q000503:physiopathology; D042241:Early Diagnosis; D005541:Forced Expiratory Volume; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D015997:Neonatal Screening; D011552:Pseudomonas Infections / Q000150:complications; D012141:Respiratory Tract Infections / Q000150:complications