Cluster differences analysis
| Cluster 1 “delayed treatment” | Cluster 2 “early diagnosis” | Cluster 3 “cardiovascular comorbidity” | p-value | |
| Patients n | 60 | 22 | 48 | |
| Age years | 68.71±9.32 | 70.34±6.40 | 69.47±6.28 | 0.691 |
| Age >75 years | 18 (30) | 5 (22.7) | 8 (16.7) | 0.268 |
| Male | 54 (90) | 20 (90.9) | 31 (64.6) | 0.002* |
| Death or transplant at 3 years | 24 (40) | 4 (18.2) | 9 (18.8) | 0.026* |
| Survival time weeks, median (IQR) | 113.0 (108.8) | 160.5 (132.8) | 134.0 (103.3) | 0.084 |
| Time from symptoms to diagnosis weeks, median (IQR) | 104.00 (118) | 48.00 (18.0) | 54.50 (86.0) | 0.007* |
| Respiratory symptoms >2 years | 29 (48.3) | 0 | 14 (29.17) | <0.001* |
| Progression at 3 years | 39 (65) | 9 (40.9) | 27 (56.3) | 0.142 |
| ≥2 respiratory infections | 12 (20) | 1 (4.6) | 10 (20.8) | 0.219 |
| ≥1 severe exacerbation | 15 (25) | 5 (22.7) | 8 (16.7) | 0.557 |
| Charlson index, median (IQR) | 4.50 (3.0) | 4.00 (1.0) | 5.00 (2.0) | 0.668 |
| FVC <50% predicted | 1 (1.7) | 1 (4.5) | 0 | 0.445 |
| DLCO <30% predicted | 9 (15.3) | 1 (4.5) | 1 (2.1) | 0.034* |
| 6MWD <350 m | 8 (13.3) | 2 (10) | 10 (20.8) | 0.426 |
| Definite HRCT UIP pattern | 60 (100) | 0 | 0 | <0.001* |
| Probable HRCT UIP pattern | 0 | 14 (63.6) | 41 (85.4) | <0.001* |
| CPFE | 13 (21.7) | 1 (4.54) | 0 | <0.001* |
| Familial pulmonary fibrosis | 12 (20) | 10 (45.5) | 14 (29.2) | 0.071 |
| Telomere shortening | 12 (20) | 8 (36.4) | 3 (6.3) | 0.006* |
| Obesity | 19 (31.7) | 1 (4.5) | 22 (45.8) | 0.002* |
| Low weight | 2 (3.3) | 0 | 0 | 0.656 |
| mMRC dyspnoea score 2–3 | 24 (40) | 0 | 29 (60.4) | <0.001* |
| Smoking exposure (≥20 pack-years) | 60 (100) | 0 | 0 | <0.001* |
| Smoking exposure (<20 pack-years) | 0 | 8 (36.4) | 25 (52.1) | <0.001* |
| OSAS treated with CPAP | 6 (10) | 0 | 8 (16.7) | 0.096 |
| Nocturnal hypoxaemia | 7 (11.7) | 1 (4.5) | 5 (10.4) | 0.741 |
| HRCT moderate and severe hiatal hernia | 26 (43.3) | 1 (4.5) | 13 (27.1) | 0.002* |
| Cardiopathy | 15 (25) | 1 (4.5) | 14 (29.2) | 0.067 |
| Pulmonary arterial hypertension | 18 (30) | 6 (27.3) | 17 (35.4) | 0.746 |
| Antifibrotic treatment stopped or switched | 20 (33.3) | 10 (45.5) | 17 (35.4) | 0.593 |
| Antifibrotic treatment stopped | 18 (30) | 3 (13.6) | 13 (27.1) | 0.322 |
| Antifibrotic treatment length weeks, median (IQR) | 90 (99.3) | 153 (41.5) | 115 (85.8) | 0.009* |
| Radiological findings without respiratory symptoms | 14 (23.3) | 11 (50) | 10 (20.8) | 0.026* |
Data are presented as n, mean±sd or n (%), unless otherwise stated. % is in relation to the cluster concerned. IQR: interquartile range; FVC: forced vital capacity; DLCO: diffusing capacity of the lung for carbon monoxide; 6MWD: 6-min walk distance; HRCT: high-resolution computed tomography; UIP: usual interstitial pneumonia; CPFE: combined pulmonary fibrosis and emphysema; mMRC: modified Medical Research Council; OSAS: obstructive sleep apnoea syndrome; CPAP: continuous positive airway pressure. *: p<0.05.