Prognostic value of desaturation during a 6-minute walk test in idiopathic interstitial pneumonia

Am J Respir Crit Care Med. 2003 Nov 1;168(9):1084-90. doi: 10.1164/rccm.200302-219OC. Epub 2003 Aug 13.


Exercise-induced hypoxia is an index of the severity of interstitial lung disease. We hypothesized that desaturation during a 6-minute walk test would predict mortality for patients with usual interstitial pneumonia (n = 83) and nonspecific interstitial pneumonia (n = 22). Consecutive patients with biopsy-proven disease performed a 6-minute walk test between January 1996 and December 2001. Desaturation was defined as a fall in oxygen saturation to 88% or less during the 6-minute walk test. Desaturation was common (44 of 83 usual interstitial pneumonia and 8 of 22 nonspecific interstitial pneumonia; chi square, p = 0.39). Patients with usual interstitial pneumonia or nonspecific interstitial pneumonia who desaturated had a significantly higher mortality than patients who did not desaturate (respective log-rank tests, p = 0.0018, p = 0.0089). In patients with usual interstitial pneumonia, the presence of desaturation was associated with an increased hazard of death (hazard ratio, 4.2; 95% confidence interval, 1.40, 12.56; p = 0.01) after adjusting for age, sex, smoking, baseline diffusion capacity for carbon monoxide, FVC, and resting saturation. We conclude that knowledge of desaturation during a 6-minute walk test adds prognostic information for patients with usual interstitial pneumonia and nonspecific interstitial pneumonia.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Cohort Studies
  • Female
  • Humans
  • Lung Diseases, Interstitial / blood
  • Lung Diseases, Interstitial / mortality
  • Lung Diseases, Interstitial / physiopathology*
  • Male
  • Middle Aged
  • Oximetry*
  • Oxyhemoglobins / metabolism
  • Prognosis
  • Walking / physiology*


  • Oxyhemoglobins