title: Disease progression in idiopathic pulmonary fibrosis without pulmonary function impairment.
abstract: OBJECTIVE
  Despite significant recent progress in the understanding of idiopathic pulmonary fibrosis (IPF), the early phase of the disease is still poorly understood. We studied patients with IPF without pulmonary function impairment in order to determine the clinical features, natural history and key findings for physiological progression.
  
  
  METHODS
  Twenty-five patients without pulmonary function impairment were identified from among patients with previously diagnosed IPF who underwent surgical lung biopsies between January 1997 and December 2006 at our institutions. 'Without pulmonary function impairment' was defined as both forced vital capacity (FVC) and diffusing capacity for carbon monoxide (DLco) >80% predicted. Patients diagnosed with IPF through multidisciplinary discussion based on the new IPF guidelines were the subjects of this study.
  
  
  RESULTS
  Sixteen patients had a confirmed diagnosis of IPF. Eleven patients presented with chest X-ray abnormality found during an annual health examination. Seven patients were asymptomatic. Eleven patients showed physiological disease progression (median time; 19.9 ± 12.3 months) defined by a decline of at least 10% in FVC or at least 15% in DLco. Univariate analysis revealed that both usual interstitial pneumonia pattern and extent of honeycombing on high-resolution computed tomography (HRCT) were factors associated with disease progression (odds ratio 5.634, 95% confidence interval 1.364-23.278; odds ratio 2.371/5%, 95% confidence interval 1.042-5.395).
  
  
  CONCLUSIONS
  IPF patients without pulmonary function impairment have a progressive but slow clinical course. The existence and extent of honeycombing on HRCT are predictive of disease progression.
authors.affiliation: Department of Respiratory Medicine and Allergy, Tosei General Hospital, Aichi, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Kondoh
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Taniguchi
authors.forename: Takashi
authors.initials: T
authors.lastname: Ogura
authors.forename: Takeshi
authors.initials: T
authors.lastname: Johkoh
authors.forename: Kiminori
authors.initials: K
authors.lastname: Fujimoto
authors.forename: Hiromitsu
authors.initials: H
authors.lastname: Sumikawa
authors.forename: Kensuke
authors.initials: K
authors.lastname: Kataoka
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Baba
authors.forename: Thomas V
authors.initials: TV
authors.lastname: Colby
authors.forename: Masanori
authors.initials: M
authors.lastname: Kitaichi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D018450:Disease Progression; D005260:Female; D006801:Humans; D054990:Idiopathic Pulmonary Fibrosis / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology*; D008168:Lung / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D014797:Vital Capacity / Q000502:physiology