title: Idiopathic organizing pneumonia: a relapsing disease. 19 years of experience in a hospital setting.
abstract: 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.
  
  
  OBJECTIVE
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Servicio de Neumologia, Hospital General Universitario de Alicante, Alicante, España.
authors.forename: Encarnacion
authors.initials: E
authors.lastname: Barroso
authors.forename: Luis
authors.initials: L
authors.lastname: Hernandez
authors.forename: Joan
authors.initials: J
authors.lastname: Gil
authors.forename: Raquel
authors.initials: R
authors.lastname: Garcia
authors.forename: Ignacio
authors.initials: I
authors.lastname: Aranda
authors.forename: Santiago
authors.initials: S
authors.lastname: Romero
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015897:Comorbidity; D018549:Cryptogenic Organizing Pneumonia / Q000175:diagnosis / Q000453:epidemiology / Q000628:therapy; D005260:Female; D006764:Hospitals, Community / Q000706:statistics & numerical data*; D006784:Hospitals, Teaching / Q000706:statistics & numerical data*; D006801:Humans; D015994:Incidence; D008137:Longitudinal Studies; D017563:Lung Diseases, Interstitial / Q000175:diagnosis / Q000453:epidemiology* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D012008:Recurrence; D012307:Risk Factors; D017678:Sex Distribution; D012907:Smoking / Q000453:epidemiology; D013030:Spain / Q000453:epidemiology; D013256:Steroids / Q000627:therapeutic use
chemical_list: D013256:Steroids