title: Validation of a predictive survival model in Italian patients with cystic fibrosis.
abstract: BACKGROUND
  In 2001 Liou published a 5-year survival model using CFF Registry data.
  
  
  OBJECTIVE
  To evaluate its validity in predicting survival in Italian CF patients.
  
  
  METHODS
  In a retrospective study on 945 patients, the 9 variables selected by Liou were analyzed, vital status on December 2008 recorded and observed and expected deaths compared. To develop a new model, patients were randomly divided into a derivation (n=475) and a validation sample (n=470).
  
  
  RESULTS
  A significant difference was found between observed and expected deaths based on Liou's model (62 vs 94), with a 34% reduction in mortality (p<0.05). A new model (based on FEV1, Staphylococcus aureus and Burkholderia cepacia complex infection, number of pulmonary exacerbations/year) was generated, that correctly predicted survival in the validation sample (31 observed vs 29 expected deaths, p=0.660).
  
  
  CONCLUSIONS
  The Liou model did not adequately predict 5-year survival in our CF population that, compared to the one in which it was originally tested, could benefit from 10 years of improvement in treatments and practice patterns. A new generated model, based on only four variables, was more accurate in predicting 5-year survival in Italian CF patients.
authors.affiliation: Italian Foundation for Research on Cystic Fibrosis, Verona, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Buzzetti
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Alicandro
authors.forename: Laura
authors.initials: L
authors.lastname: Minicucci
authors.forename: Sara
authors.initials: S
authors.lastname: Notarnicola
authors.forename: Maria Lucia
authors.initials: ML
authors.lastname: Furnari
authors.forename: Gabriella
authors.initials: G
authors.lastname: Giordano
authors.forename: Vincenzina
authors.initials: V
authors.lastname: Lucidi
authors.forename: Enza
authors.initials: E
authors.lastname: Montemitro
authors.forename: Valeria
authors.initials: V
authors.lastname: Raia
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Magazzù
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Vieni
authors.forename: Serena
authors.initials: S
authors.lastname: Quattrucci
authors.forename: Alessandro
authors.initials: A
authors.lastname: Ferrazza
authors.forename: Rolando
authors.initials: R
authors.lastname: Gagliardini
authors.forename: Natalia
authors.initials: N
authors.lastname: Cirilli
authors.forename: Donatello
authors.initials: D
authors.lastname: Salvatore
authors.forename: Carla
authors.initials: C
authors.lastname: Colombo
mesh_terms: D000293:Adolescent; D016009:Chi-Square Distribution; D003550:Cystic Fibrosis / Q000382:microbiology / Q000401:mortality*; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D016015:Logistic Models; D008297:Male; D011379:Prognosis; D011552:Pseudomonas Infections / Q000401:mortality; D011550:Pseudomonas aeruginosa; D016019:Survival Analysis; D055815:Young Adult