Table 1.
Characteristics of patients with progressive ILD and a stable disease course
| Variable | Progressive ILD (N = 50) | Stable disease (N = 47) | P value |
|---|---|---|---|
| Gender (male) | 28 (56) | 32 (68) | 0.221 |
| Age (years) | 67.0 (60.8–69.3) | 69.0 (60.0–75.0) | 0.365 |
| BMI (kg/m2) | 28.2 (26.4–32.0) | 28.1 (25.1–30.7) | 0.264 |
| Antifibrotic treatment | 19 (38) | 16 (34) | 0.685 |
| Immunosuppressive therapya | 22 (40) | 15 (32) | 0.221 |
| Never smoker | 24 (48) | 12 (25) | |
| Former smoker | 18 (36) | 30 (64) | 0.008* |
| Current smoker | 8 (16) | 5 (11) | |
| Pack years (smokers only) | 20.0 (10.0–30.0) 23/26 | 20.0 (15.0–30.0) 33/35 | 0.492 |
| FVC % | 78.5 (69.5–91.0) | 83.0 (72.0–89.0) | 0.267 |
| FEV1% | 82.0 (72.5–91.0) | 83.0 (73.0–91.0) | 0.829 |
| DLCO % | 61.5 (48.8–73.0) | 63.5 (51.4–71.3) 46/47 | 0.498 |
| White blood cells (109/L) | 7.4 (6.0-9.3) | 6.9 (5.5–8.1) | 0.089 |
| Hemoglobin (g/L) | 137.5 (129.5-150.3) | 143.0 (134.0-154.0) | 0.196 |
| Platelets (109/L) | 243.5 (212.3-310.3) | 241.0 (199.0-277.0) | 0.067 |
| Creatinin (umol/L) | 75.0 (64.8–91.3) | 76.0 (69.0–91.0) | 0.530 |
| GFR (ml/min/1.73m2) | 84.0 (66.8–93.3) | 84.0 (68.5–92.0) | 0.847 |
| LCQ total score | 16.5 (13.5–19.1) | 16.1 (12.4–18.4) | 0.411 |
| SGRQ total score | 31.9 (14.5–51.7) 46/50 | 30.9 (16.4–38.4) 43/47 | 0.837 |
| SOBQ total score | 31.5 (7.50–51.0) | 22.0 (11.0–40.0) | 0.662 |
| Ground-glass opacity score | 3.0 (0.6–5.5) | 1.5 (0.0-3.8) 41/47 | 0.105 |
| Reticulation score | 10.0 (7.9–12.0) | 8.5 (6.0–10.0) 40/47 | 0.022 |
| Emphysema score | 0.0 (0.0–0.0) | 0.0 (0.0-2.3) 44/47 | 0.158 |
| Traction bronchiectasis score | 3.5 (2.0-4.6) | 2.5 (1.0–4.0) 44/47 | 0.070 |
| Honeycombing score | 0.0 (0.0-1.1) | 0.0 (0.0-0.9) 44/47 | 0.157 |
| UIP histopathology | 12 (24) | 10 (21) | 0.749 |
| UIP pattern on HRCTb | 0.544 | ||
| Definite UIP | 2 (4) | 2 (4) | |
| Probable UIP | 13 (26) | 16 (34) | |
| Indeterminate with UIP | 22 (44) | 14 (30) | |
| Alternative diagnosis | 13 (26) | 15 (32) | |
| Diagnosis | 0.699 | ||
| Idiopathic pulmonary fibrosis | 32 (64) | 31 (66) | |
| Idiopathic nonspecific interstitial pneumonia | 9 (18) | 5 (11) | |
| Hypersensitivity pneumonia | 5 (10) | 5 (11) | |
| Unclassified ILD | 3 (6) | 2 (4) | |
| Respiratory bronchiolitis associated ILD | 1 (2) | - | |
| Connective tissue disease associated ILD | - | 1 (2) | |
| Asbestosis | - | 1 (2) | |
| Cryptogenic organizing pneumonia | - | 1 (2) | |
| Fibrotic sarcoidosis | - | 1 (2) |
Numbers are presented as N (%) or median (interquartile range, IQR). BMI = body mass index, DLCO % = diffusion capacity to carbon monoxide, FEV1% = forced expiratory volume in one second percent predicted, FVC % = forced vital capacity percent predicted, GFR = glomerular filtration rate, ILD = interstitial lung disease, LCQ = Leicester cough questionnaire, SGRQ = St George respiratory questionnaire, SOBQ = University of California shortness of breath questionnaire, UIP = usual interstitial pneumonia
*P value between former smoker- never smoker. a. Including the use of oral corticosteroids, azathioprine, or mycophenolate. b. Re-categorized for this study, some of the results have been published previously [31]