Idiopathic organizing pneumonia: a relapsing disease. 19 years of experience in a hospital setting

Respiration. 2007;74(6):624-31. doi: 10.1159/000103240. Epub 2007 May 24.


Background: Although organizing pneumonia (OP) is a common pathological finding, studies including a substantial number of patients with idiopathic forms from a unique center and a long follow-up are rare.

Objectives: To determine patients with cryptogenic forms of organizing pneumonia (COP), in order to characterize their clinical course, to identify predictive factors for relapse and to assess their effect on outcome.

Methods: For a 19-year period, all histopathological reports from a community teaching hospital were reviewed, and OP was found in 210 lung specimens belonging to 197 patients.

Results: Thirty-three (17%) patients presented cryptogenic forms and 32 of them (97%) responded to steroid therapy. At follow-up, 14 patients presented no relapses (no-relapse group, NR) and 18 (56%) presented relapses (relapsing group, RG) that resolved with ulterior treatment. Multifocal opacities on chest X-ray (RG 83% vs. NR 36%, p = 0.02) appeared to be a predictor for relapse. Patients with relapses showed a shorter time span to chest X-ray normalization (RG 8 +/- 8 weeks vs. NR 13 +/- 9 weeks, p = 0.09) that became significant in patients with 3 or more relapses (multiple-relapse group, MR, 4 +/- 2 weeks vs. NR 13 +/- 9 weeks, p < 0.04). Although the initial prednisone dose was similar in patients with relapsing forms, its maintenance was shorter than in patients without relapses, showing a trend to significance (RG 4 +/- 3 weeks, NR 7 +/- 6 weeks, p = 0.09). Lower levels of lactate dehydrogenase and gamma-glutamyltransferase, although always within the normal range, were found in patients with relapsing forms.

Conclusion: COP is a specific but infrequent form of OP with a good response to steroid therapy. Relapses are frequent and typical characteristics of COP which resolved with ulterior treatment. Multifocal opacities on chest X-ray and a shorter maintenance of the initial steroid dose may increase the risk of relapse.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Comorbidity
  • Cryptogenic Organizing Pneumonia / diagnosis
  • Cryptogenic Organizing Pneumonia / epidemiology
  • Cryptogenic Organizing Pneumonia / therapy
  • Female
  • Hospitals, Community / statistics & numerical data*
  • Hospitals, Teaching / statistics & numerical data*
  • Humans
  • Incidence
  • Longitudinal Studies
  • Lung Diseases, Interstitial / diagnosis
  • Lung Diseases, Interstitial / epidemiology*
  • Lung Diseases, Interstitial / therapy
  • Male
  • Middle Aged
  • Outcome Assessment, Health Care
  • Recurrence
  • Risk Factors
  • Sex Distribution
  • Smoking / epidemiology
  • Spain / epidemiology
  • Steroids / therapeutic use


  • Steroids