title: Presence of a prothrombotic state in people with idiopathic pulmonary fibrosis: a population-based case-control study.
abstract: BACKGROUND
  Laboratory studies suggest that the clotting cascade is activated in fibrotic lungs. Since humans vary in their tendency to clot due to a variety of inherited or acquired defects, we investigated whether a prothrombotic state increases the chance of developing idiopathic pulmonary fibrosis (IPF) and/or worsens the prognosis of IPF.
  
  
  METHODS
  We recruited 211 incident cases of IPF and 256 age- and sex-matched general population controls and collected data on medical history, medication, smoking habit, blood samples as well as lung function and high-resolution CT scans done as part of routine clinical care. A prothrombotic state was defined as the presence of at least one inherited or acquired clotting defect or marker of fibrinolytic dysfunction. We used logistic regression to quantify the association between a prothrombotic state and IPF adjusted for age, sex, smoking habit and highly sensitive C reactive protein. Cox regression was used to determine the influence of a prothrombotic state on survival.
  
  
  RESULTS
  Cases were more than four times more likely than controls to have a prothrombotic state (OR 4.78, 95% CI 2.93 to 7.80; p<0.0001). Cases with a prothrombotic state were also likely to have more severe disease (forced vital capacity <70% predicted) at presentation (OR 10.79, 95% CI 2.43 to 47.91) and had a threefold increased risk of death (HR 3.26, 95% CI 1.09 to 9.75).
  
  
  CONCLUSIONS
  People with IPF are more likely to have a prothrombotic state than general population controls and the presence of a prothrombotic state has an adverse impact on survival.
authors.affiliation: Division of Epidemiology and Public Health, University of Nottingham, , Nottingham, UK.
authors.forename: Vidya
authors.initials: V
authors.lastname: Navaratnam
authors.forename: Andrew W
authors.initials: AW
authors.lastname: Fogarty
authors.forename: Tricia
authors.initials: T
authors.lastname: McKeever
authors.forename: Norma
authors.initials: N
authors.lastname: Thompson
authors.forename: Gisli
authors.initials: G
authors.lastname: Jenkins
authors.forename: Simon R
authors.initials: SR
authors.lastname: Johnson
authors.forename: Gerard
authors.initials: G
authors.lastname: Dolan
authors.forename: Maruti
authors.initials: M
authors.lastname: Kumaran
authors.forename: Kate
authors.initials: K
authors.lastname: Pointon
authors.forename: Richard B
authors.initials: RB
authors.lastname: Hubbard
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000378:metabolism*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D054990:Idiopathic Pulmonary Fibrosis / Q000097:blood* / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000401:mortality; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D011516:Prothrombin / Q000378:metabolism*; D012307:Risk Factors; D012680:Sensitivity and Specificity; D016019:Survival Analysis; D014057:Tomography, X-Ray Computed; D014797:Vital Capacity
chemical_list: D015415:Biomarkers; D011516:Prothrombin; D002097:C-Reactive Protein
keywords: Idiopathic pulmonary fibrosis; Interstitial Fibrosis