Walking distance on 6-MWT is a prognostic factor in idiopathic pulmonary fibrosis

Respir Med. 2009 Jan;103(1):117-23. doi: 10.1016/j.rmed.2008.07.022. Epub 2008 Sep 10.


Background and aim of the work: Idiopathic pulmonary fibrosis (IPF) is a progressive disease with high mortality rates and a median survival of 2-3 years from time of diagnosis. The prognosis for any individual patient, however, is variable. To elucidate the clinical significance of 6-min walking test (6-MWT) in patients with IPF, we sought to assess the relationship between distance walked and desaturation during this test and pulmonary function tests (PFTs). We also evaluate the prognostic value of 6-MWT in comparison with PFTs at baseline and during follow-up.

Methods: The clinical data of 44 patients with IPF were retrospectively analysed. Twenty-nine patients had an additional evaluation after 12 month of follow-up.

Results: Distance walked in 6 min was independently related to mortality by multivariate analysis. Patients walking less then 212 m had a significantly lower survival than those walking farther, assessed by Kaplan-Meier survival curves (log-rank test, p<0.036). During a mean follow-up period of 19.8 months (range 3.2-46.4), 11 patients died of causes related to disease. Changes in meters walked at 12 months evaluation were also predictive of survival (p=0.05).

Conclusions: These results confirm that in IPF distance walked in 6 min is independent associated with mortality.

MeSH terms

  • Area Under Curve
  • Exercise Test / methods
  • Exercise Tolerance*
  • Female
  • Follow-Up Studies
  • Humans
  • Idiopathic Pulmonary Fibrosis / mortality
  • Idiopathic Pulmonary Fibrosis / physiopathology*
  • Kaplan-Meier Estimate
  • Lung / physiopathology
  • Male
  • Middle Aged
  • Prognosis
  • Proportional Hazards Models
  • Retrospective Studies
  • Survival Rate
  • Time Factors
  • Vital Capacity
  • Walking*