title: Impact of lung function interpretation approach on pediatric bronchiolitis obliterans syndrome diagnosis after lung transplantation.
abstract: BACKGROUND
  The diagnostic criteria for bronchiolitis obliterans syndrome (BOS) are predominantly adult-focused. The relationship between application and impact of reference equation choice on pediatric baseline lung function achieved and subsequent BOS diagnosis remains unclear.
  
  
  METHODS
  Lung function spirometry data (FEV(1), FVC and FEF(25-75)) from pediatric subjects transplanted at the Great Ormond Street Hospital over a 10-year period were collated. Baseline values achieved after lung transplantation and BOS rates were examined. Raw values were compared with 2 different reference equations (the "Brompton" and modern collated "All-age" equations). The impact of FEF(25-75) baseline definition was investigated.
  
  
  RESULTS
  Fifty subjects were included, 17 males and 33 females, transplanted at a median (range) age of 14.0 years (3.2 to 17.3 years, 83% >10 years old), and followed for 1,028 (388 to 2,613) days post-transplantation. Raw values underestimated baseline lung function attainment for all indices. Magnitude of baseline lung function was affected by reference equation choice. Mean FEV(1) values were: Brompton 97.9% (SD 20.3%) and All-age 86.3% (SD 15.4%) of predicted (p < 0.0001). BOS 0p incidence was significantly higher for All-age predicted than for raw values (64% and 40%, respectively, p = 0.027). Modification of FEF(25-75) baseline (to either FEV(1) or FVC baseline) led to a reduction in BOS 0p detection (p < 0.01).
  
  
  CONCLUSIONS
  Modern collated reference equations should be used for lung function monitoring in pediatric subjects after lung transplantation. Standardization of FEF(25-75) baseline definition is urgently required. These data question the utility of the FEF(25-75) criterion as an early marker of BOS 0p in pediatric subjects.
authors.affiliation: Department of Respiratory Medicine, The Children's Hospital at Westmead, Sydney, New South Wales, Australia; Department of Cardiothoracic Transplantation, Great Ormond Street Hospital for Children NHS Trust, London, UK; Discipline of Pediatrics and Child Health, Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia. Electronic address: dr.pdrobinson@gmail.com.
authors.forename: Paul D
authors.initials: PD
authors.lastname: Robinson
authors.affiliation: Department of Cardiothoracic Transplantation, Great Ormond Street Hospital for Children NHS Trust, London, UK.
authors.forename: Helen
authors.initials: H
authors.lastname: Spencer
authors.affiliation: Department of Cardiothoracic Transplantation, Great Ormond Street Hospital for Children NHS Trust, London, UK.
authors.forename: Paul
authors.initials: P
authors.lastname: Aurora
mesh_terms: D000293:Adolescent; D000367:Age Factors; D001989:Bronchiolitis Obliterans / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D005540:Forced Expiratory Flow Rates / Q000502:physiology; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D015994:Incidence; D053208:Kaplan-Meier Estimate; D016040:Lung Transplantation / Q000009:adverse effects*; D008297:Male; D012189:Retrospective Studies; D013147:Spirometry; D014797:Vital Capacity / Q000502:physiology
keywords: bronchiolitis obliterans syndrome; lung function; monitoring; pediatric; reference equations; spirometry