title: Incidence, prevalence, and clinical course of idiopathic pulmonary fibrosis: a population-based study.
abstract: BACKGROUND
  Limited data exist regarding the population-based epidemiology of idiopathic pulmonary fibrosis (IPF). The objective of the study was to describe the trends in the incidence, prevalence, and clinical course of IPF in the community.
  
  
  METHODS
  We conducted a population-based study of adult patients with IPF in Olmsted County, Minnesota, from 1997 to 2005. Two methods were used to identify IPF cases, as defined by the 2002 American Thoracic Society/European Respiratory Society consensus statement: (1) usual interstitial pneumonia (UIP) on a surgical lung biopsy specimen or a definite UIP pattern on a high-resolution CT image (narrow criteria) and (2) UIP on a surgical lung biopsy specimen or a definite or possible UIP pattern on CT image (broad criteria).
  
  
  RESULTS
  Of 596 patients screened for the possibility of pulmonary disease or pulmonary fibrosis over 9 years of follow-up, 47 cases had IPF. Of these, 24 met the narrow criteria. The age- and sex-adjusted incidence was 8.8/100,000 and 17.4/100,000 person-years, for narrow and broad criteria, respectively. The age-adjusted incidence was higher in men than in women, and among patients aged 70-79 years. During the study period, the incidence of IPF decreased (P < .001). On December 31, 2005, the age- and sex-adjusted prevalence was 27.9/100,000 and 63/100,000 persons by narrow and broad criteria, respectively. Thirty-seven patients experienced a total of 53 respiratory exacerbations (26 IPF related, 27 non-IPF related), and 34 (72%) patients died. The primary cause of death was IPF related in 16 (47%) patients. Median survival for narrow-criteria and broad-criteria incidence cases was 3.5 and 4.4 years, respectively.
  
  
  CONCLUSIONS
  The incidence of IPF in Olmsted County decreased over the study period. Nonprimary IPF respiratory exacerbations are as frequent as primary IPF respiratory exacerbations and an important cause of death.
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Autoimmune Lung Center and Interstitial Lung Disease Program, National Jewish Health, 1400 Jackson Street G-10a, Denver, CO 80206, USA. FernandezEvans@NJHealth.org
authors.forename: Evans R
authors.initials: ER
authors.lastname: Fernández Pérez
authors.forename: Craig E
authors.initials: CE
authors.lastname: Daniels
authors.forename: Darrell R
authors.initials: DR
authors.lastname: Schroeder
authors.forename: Jennifer
authors.initials: J
authors.lastname: St Sauver
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Hartman
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Bartholmai
authors.forename: Eunhee S
authors.initials: ES
authors.lastname: Yi
authors.forename: Jay H
authors.initials: JH
authors.lastname: Ryu
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D003937:Diagnosis, Differential; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D054990:Idiopathic Pulmonary Fibrosis / Q000175:diagnosis / Q000453:epidemiology*; D015994:Incidence; D008297:Male; D008875:Middle Aged; D008910:Minnesota / Q000453:epidemiology; D011159:Population Surveillance / Q000379:methods*; D015995:Prevalence; D012189:Retrospective Studies; D015996:Survival Rate / Q000639:trends; D014057:Tomography, X-Ray Computed