title: Early detection of lung function decrements in children and adolescents with cystic fibrosis using new reference values.
abstract: Interpretation of lung function values in children with cystic fibrosis (CF) depends on the applied reference values. We hypothesize that differences between the new global lung function initiative (GLI) values and the formerly used Zapletal et al. values produce significantly different clinical results. We analyzed 3719 lung function measurements of 108 children and adolescents (n = 54 male; aged 6-18 years) with CF treated between September 1991 and July 2009. Data were analyzed in milliliters (ml) and % predicted (pred.) and interpreted using Zapletal and GLI reference values. Applying GLI compared to Zapletal resulted in significantly lower mean forced expiratory volume in 1s (FEV1)% pred.
  
  
  METHODS
  Zapletal 86.6% (SD 20.6), GLI 79.9% (SD 20.3) and 32% (n = 497/1543) were misclassified as normal when using Zapletal. Despite showing no overall differences in FEV1 and forced vital capacity (FVC) between concomitant Pseudomonas detection (PA+) in n = 938 and Pseudomonas negative (PA-) (n = 2781) using either reference PA+ resulted in lower FEV1 and FVC values with increasing age; however, measurement of small airway obstruction with forced expiratory flow at 75% of FVC (FEF75) values - available for Zapletal -showed significant differences. Reassurance regarding lung function when using old reference values may occur with potential clinical significance. Discrepancies in lung function interpretation underline the importance of using uniform and best available reference values.
authors.affiliation: Department of Pediatrics and Adolescent Medicine, Wilhelminenspital Vienna, Montleartstrasse 37, 1160, Vienna, Austria. angela.zacharasiewicz@wienkav.at.
authors.forename: Angela
authors.initials: A
authors.lastname: Zacharasiewicz
authors.affiliation: Department of Pediatrics, Medical University Hospital Vienna, Vienna, Austria.
authors.forename: Sabine
authors.initials: S
authors.lastname: Renner
authors.affiliation: Department of Pediatrics, Medical University Hospital Vienna, Vienna, Austria.
authors.forename: Flora
authors.initials: F
authors.lastname: Haderer
authors.affiliation: Department of Biomedical Imaging and Image Guided Therapy, Medical University Vienna, Vienna, Austria.
authors.forename: Michael
authors.initials: M
authors.lastname: Weber
authors.affiliation: Department of Pediatrics, Medical University Hospital Vienna, Vienna, Austria.|Department of Pediatrics, The Royal Brompton Hospital, Sydney Street, SW3 6NP, London, UK.
authors.forename: Eleonore
authors.initials: E
authors.lastname: Dehlink
authors.affiliation: Department of Pediatrics, Medical University Hospital Vienna, Vienna, Austria.
authors.forename: Zsolt
authors.initials: Z
authors.lastname: Szepfalusi
authors.affiliation: Department of Pediatrics and Adolescent Medicine, Wilhelminenspital Vienna, Montleartstrasse 37, 1160, Vienna, Austria.|Department of Pediatrics, Medical University Hospital Vienna, Vienna, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Frischer
mesh_terms: D000293:Adolescent; D000367:Age Factors; D001317:Austria; D002648:Child; D003550:Cystic Fibrosis / Q000175:diagnosis* / Q000473:pathology; D042241:Early Diagnosis; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008297:Male; D011552:Pseudomonas Infections / Q000175:diagnosis; D012016:Reference Values; D012129:Respiratory Function Tests; D012680:Sensitivity and Specificity; D014797:Vital Capacity
keywords: Children; Cystic fibrosis; Lung function; Reference values; Spirometry