title: Estimating peak oxygen uptake in adolescents with cystic fibrosis.
abstract: OBJECTIVE
  To predict peak oxygen uptake (VO2 peak) from the peak work rate (W peak) obtained during a cycle ergometry test using the Godfrey protocol in adolescents with cystic fibrosis (CF), and assess the accuracy of the model for prognostication clustering.
  
  
  METHODS
  Out of our database of anthropometric, spirometric and maximal exercise data from adolescents with CF (N=363; 140 girls and 223 boys; age 14.77 ± 1.73 years; mean expiratory volume in 1 s (FEV1%pred) 86.82 ± 17.77%), a regression equation was developed to predict VO2 peak (mL/min). Afterwards, this prediction model was validated with cardiopulmonary exercise data from another 60 adolescents with CF (28 girls, 32 boys; mean age 14.6 ± 1.67 years; mean FEV1%pred 85.43 ± 20.01%).
  
  
  RESULTS
  We developed a regression model VO2 peak (mL/min)=216.3-138.7 × sex (0=male; 1=female)+11.5 × W peak; R(2)=0.91; SE of the estimate (SEE) 172.57. A statistically significant difference (107 mL/min; p<0.001) was found between predicted VO2 peak and measured VO2 peak in the validation group. However, this difference was not clinically relevant because the difference was within the SEE of the model. Furthermore, we found high positive predictive and negative predictive values for the model for prognostication clustering (PPV 50-87% vs NPV 82-94%).
  
  
  CONCLUSIONS
  In the absence of direct VO2 peak assessment it is possible to estimate VO2 peak in adolescents with CF using only a cycle ergometer. Furthermore, the regression model showed to be able to discriminate patients in different prognosis clusters based on exercise capacity.
authors.affiliation: Child Development & Exercise Center, Wilhelmina Children's Hospital, University Medical Center Utrecht, , Utrecht, The Netherlands.
authors.forename: Maarten S
authors.initials: MS
authors.lastname: Werkman
authors.forename: Erik H J
authors.initials: EH
authors.lastname: Hulzebos
authors.forename: Paul J M
authors.initials: PJ
authors.lastname: Helders
authors.forename: Bert G M
authors.initials: BG
authors.lastname: Arets
authors.forename: Tim
authors.initials: T
authors.lastname: Takken
mesh_terms: D000293:Adolescent; D003550:Cystic Fibrosis / Q000503:physiopathology*; D016552:Ergometry; D005080:Exercise Test / Q000379:methods*; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology*; D011379:Prognosis
keywords: Cystic Fibrosis; Exercise; Paediatric Lung Disaese