Patient demographics and disease characteristics
| Characteristic | |
| Patients n | 20 |
| Age years | |
| Mean±sd | 70.1±9.5 |
| Median (range) | 72.5 (48–81) |
| Female n (%) | 10 (50) |
| Smoking status n (%) | |
| Current smoker | 1 (5) |
| Previous smoker | 7 (35) |
| Non-smoker | 12 (60) |
| Duration since ILD diagnosis based on imaging years | |
| Mean±sd | 4.3±3.1 |
| Median (range) | 3.0 (1.8–12.5) |
| Underlying ILD diagnosis n (%) | |
| Rheumatoid arthritis-associated ILD | 5 (25) |
| Mixed connective tissue disease | 4 (20) |
| Hypersensitivity pneumonitis | 3 (15) |
| Systemic sclerosis-associated ILD | 2 (10) |
| Respiratory bronchiolitis with ILD | 2 (10) |
| Other fibrotic ILD# | 4 (20) |
| Diagnosed with usual interstitial pneumonia pattern¶ n (%) | |
| Yes | 6 (30) |
| No | 14 (70) |
| FVC % predicted | |
| Mean±sd | 67.0±13.6 |
| Median (range) | 66.5 (47–95) |
| DLCO % predicted | |
| Mean±sd | 51.6±9.7 |
| Median (range) | 53.0 (35–66) |
| Comorbidities n (%)+ | |
| History of unstable or deteriorating cardiac disease | 1 (5) |
| COPD | 4 (20) |
| Sleep disorders | 3 (15) |
| GORD | 12 (60) |
| Articular joint involvement | 1 (5) |
| Other | 15 (75) |
| None | 2 (10) |
| Supplemental oxygen use n (%) | 7 (35) |
| BMI | |
| Mean±sd | 26.8±4.6 |
| Median (range) | 26.9 (20–36) |
ILD: interstitial lung disease; FVC: forced vital capacity; DLCO: diffusing capacity of the lungs for carbon monoxide; GORD: gastro-oesophageal reflux disease; BMI: body mass index. #: systemic lupus (n=1), byssinosis (n=1), drug toxicity (n=1), inflammatory bowel disease-related ILD (n=1); ¶: defined based on the American Thoracic Society/European Respiratory Society/Japanese Respiratory Society/Latin American Thoracic Association 2011 guidelines; +: not mutually exclusive.