title: Six-minute-walk distance predicts waiting list survival in idiopathic pulmonary fibrosis.
abstract: BACKGROUND
  Functional studies may be useful to predict survival in idiopathic pulmonary fibrosis (IPF). Various cutoffs of 6-min-walk distance (6MWD) have been suggested to identify patients at a high risk of death.
  
  
  OBJECTIVE
  To examine the association between 6MWD and survival in patients with IPF listed for lung transplantation, and to identify sensitive and specific cutoffs for predicting death at 6 mo.
  
  
  METHODS
  We performed a retrospective cohort study of 454 patients classified as having IPF listed for lung transplantation with the United Network for Organ Sharing between June 30, 2004 and July 22, 2005.
  
  
  RESULTS
  Lower 6MWD was associated with an increased mortality rate (p value for linear trend < 0.0001). Patients with a walk distance less than 207 m had a more than fourfold greater mortality rate than those with a walk distance of 207 m or more, despite adjustment for demographics, anthropomorphics, FVC % predicted, pulmonary hypertension, and medical comorbidities (adjusted rate ratio, 4.7; 95% confidence interval, 2.5-8.9; p < 0.0001). 6MWD was a significantly better predictor of 6-mo mortality than was FVC % predicted (c-statistic = 0.73 vs. 0.59, respectively; p = 0.02).
  
  
  CONCLUSIONS
  Lower 6MWD was strongly and independently associated with an increased mortality rate for wait-listed patients classified as having IPF. 6MWD was a better predictor of death at 6 mo than was FVC % predicted.
authors.affiliation: Department of Medicine, College of Physicians and Surgeons, Joseph L. Mailman School of Public Health, Columbia University, New York, New York 10032, USA.
authors.forename: David J
authors.initials: DJ
authors.lastname: Lederer
authors.forename: Selim M
authors.initials: SM
authors.lastname: Arcasoy
authors.forename: Jessie S
authors.initials: JS
authors.lastname: Wilt
authors.forename: Frank
authors.initials: F
authors.lastname: D'Ovidio
authors.forename: Joshua R
authors.initials: JR
authors.lastname: Sonett
authors.forename: Steven M
authors.initials: SM
authors.lastname: Kawut
mesh_terms: D005080:Exercise Test / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D016040:Lung Transplantation; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D011658:Pulmonary Fibrosis / Q000401:mortality* / Q000503:physiopathology* / Q000601:surgery; D011669:Pulmonary Wedge Pressure; D012372:ROC Curve; D012189:Retrospective Studies; D015996:Survival Rate / Q000639:trends; D013997:Time Factors; D014850:Waiting Lists; D016138:Walking / Q000502:physiology*