Table 1

Cohort characteristics by HRCT pattern

HRCTHRCT
Possible UIPInconsistent with UIP
CharacteristicDerivation (n=64)Validation (n=71)Derivation (n=321)Validation (n=95)
Age in years, mean (SD)65 (8)68 (8)59 (12)61 (12)
Male sex, n (%)40 (62.5)47 (66.0)134 (41.7)50 (53.0)
Ever smoker, n (%)36 (56.2)42 (59.0)174 (54.2)47 (49.0)
Race/ethnicity, n (%)
 White or Caucasian48 (75.0)69 (97.0)238 (74.1)90 (95.0)
 Hispanic or Latino9 (14.1)2 (3.0)31 (9.7)2 (2.0)
 Asian5 (7.8)016 (5.0)1 (1.0)
 Black or African2 (3.1)014 (4.4)1 (1.0)
 American
 Native American008 (2.5)0
 Other007 (2.2)1 (1.0)
 Unknown/declined007 (2.2)0
PFTs, mean (SD)
 FVC, % predicted70.8 (18.9)69.1 (16.2)70.6 (18.9)61.9 (13.8)
 FEV1, % predicted75.7 (19.4)74.2 (15.7)75.4 (19.7)64.8 (14.7)
 TLC, % predicted74.0 (17.1)68.1 (12.1)74.3 (17.6)67.2 (12.3)
 DLCO, % predicted53.1 (19.0)47.5 (14.3)53.5 (19.4)46.3 (12.1)
Clinical diagnosis, n (%)
 IPF39 (60.9)69 (97.0)57 (17.8)49 (46.0)
 HP12 (18.8)2 (3.0)89 (27.7)25 (26.0)
 CTD-ILD*3 (4.7)017 (5.3)4 (4.0)
 Idiopathic NSIP1 (1.6)025 (7.8)7 (7.0)
 Undifferentiated CTD2 (3.1)023 (7.2)0
 Unclassifiable ILD7 (10.9)052 (16.2)6 (6.3)
 Other†0058 (18.1)4 (4.2)
  • *CTD-ILD diagnosed after surgical lung biopsy included:

  • UCSF cohort: Anti-neutrophil cytoplasmic antibody-associated vasculitis (n=1), inflammatory myositis (n=9), mixed connective tissue disease (n=1), rheumatoid arthritis (n=3), systemic lupus erythematosus (n=1) and scleroderma (n=4). Mayo cohort: Sjogren's syndrome (n=1), inflammatory myositis (n=1), mixed connective tissue disease (n=1), scleroderma (n=1).

  • †Other diagnoses included:

  • UCSF cohort: Asbestosis (n=1), bronchiolitis (n=8), cryptogenic organising pneumonia (n=7), diffuse alveolar haemorrhage (n=1), desquamative interstitial pneumonia (n=8), dyskeratosis congenita (n=1), eosinophilic pneumonia (n=2), familial pulmonary fibrosis (n=1), mycobacterium avium complex (n=2), lymphocytic interstitial pneumonia (n=3), methotrexate toxicity (n=1), nitrofurantoin toxicity (n=1), not ILD (n=1), surfactant protein C mutation (n=1), light chain deposition disease (n=1), lipoid pneumonia (n=1), respiratory bronchiolitis ILD (n=3), sarcoidosis (n=15).

  • Mayo Cohort: Desquamative interstitial pneumonia (n=4).

  • CTD, connective tissue disease; HP, hypersensitivity pneumonitis; HRCT, high-resolution CT; ILD, interstitial lung disease; IPF, idiopathic pulmonary fibrosis; DLCO, diffusing capacity for carbon monoxide; NSIP, non-specific interstitial pneumonitis; PFTs, pulmonary function tests; TLC, total lung capacity; UCSF, University of California, San Francisco; UIP, usual interstitial pneumonia.