Table 1. Cohort characteristics by HRCT pattern.
| HRCT | HRCT | |||
|---|---|---|---|---|
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| Possible UIP | Inconsistent with UIP | |||
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| Characteristic | Derivation (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 Caucasian | 48 (75.0) | 69 (97.0) | 238 (74.1) | 90 (95.0) |
| Hispanic or Latino | 9 (14.1) | 2 (3.0) | 31 (9.7) | 2 (2.0) |
| Asian | 5 (7.8) | 0 | 16 (5.0) | 1 (1.0) |
| Black or African | 2 (3.1) | 0 | 14 (4.4) | 1 (1.0) |
| American | ||||
| Native American | 0 | 0 | 8 (2.5) | 0 |
| Other | 0 | 0 | 7 (2.2) | 1 (1.0) |
| Unknown/declined | 0 | 0 | 7 (2.2) | 0 |
| PFTs, mean (SD) | ||||
| FVC, % predicted | 70.8 (18.9) | 69.1 (16.2) | 70.6 (18.9) | 61.9 (13.8) |
| FEV1, % predicted | 75.7 (19.4) | 74.2 (15.7) | 75.4 (19.7) | 64.8 (14.7) |
| TLC, % predicted | 74.0 (17.1) | 68.1 (12.1) | 74.3 (17.6) | 67.2 (12.3) |
| DLCO, % predicted | 53.1 (19.0) | 47.5 (14.3) | 53.5 (19.4) | 46.3 (12.1) |
| Clinical diagnosis, n (%) | ||||
| IPF | 39 (60.9) | 69 (97.0) | 57 (17.8) | 49 (46.0) |
| HP | 12 (18.8) | 2 (3.0) | 89 (27.7) | 25 (26.0) |
| CTD-ILD* | 3 (4.7) | 0 | 17 (5.3) | 4 (4.0) |
| Idiopathic NSIP | 1 (1.6) | 0 | 25 (7.8) | 7 (7.0) |
| Undifferentiated CTD | 2 (3.1) | 0 | 23 (7.2) | 0 |
| Unclassifiable ILD | 7 (10.9) | 0 | 52 (16.2) | 6 (6.3) |
| Othert† | 0 | 0 | 58 (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.