Patient characteristics and risk factors in the total cohort by idiopathic pulmonary fibrosis (IPF) disease duration
| Patients | Total cohort | Subgroups | |||
| Prevalent IPF# | Incident IPF¶ | p-value | |||
| Patients | 502 | 331 | 171 | ||
| Males | 502 | 391 (77.9) | 243 (73.4) | 148 (86.6) | 0.001 |
| Age years | 502 | 68.7±9.4 | 67.5±9.8 | 71.0±8.0 | <0.001 |
| Body mass index kg·m−2 | 502 | 27.6±4.1 | 27.4±4.2 | 28.2±3.8 | 0.048 |
| Smoking status | 502 | ||||
| Never | 195 (38.8) | 140 (42.3) | 55 (32.2) | 0.087 | |
| Previous | 302 (60.2) | 188 (56.8) | 114 (66.7) | ||
| Current | 5 (1.0) | 3 (0.9) | 2 (1.2) | ||
| 6-min walk distance m | 502 | 267.6±199.7 | 266.7±198.7 | 269.4±202.1 | 0.886 |
| Symptom duration months | 458 | 46.9±52.5 | 57.6±54.4 | 27.2±42.3 | <0.001 |
| Disease duration months | 498 | 27.6±41.9 | 41.3±46.2 | 1.4±2.0 | 0.036 |
| Risk factors | 502 | ||||
| Environmental exposure | 136 (27.1) | 80 (24.2) | 56 (32.8) | 0.028 | |
| Gastro-oesophageal reflux | 148 (29.5) | 106 (32.0) | 42 (24.6) | 0.136 | |
| Genetic predisposition | 20 (4.0) | 13 (3.9) | 7 (4.1) | 0.887 | |
| Exposure to drugs associated with IPF | 8 (1.6) | 5 (1.5) | 3 (1.8) | 0.309 | |
Data are presented as n, n (%) or mean±sd, unless otherwise stated. #: duration since diagnosis ≥6 months; ¶: duration since diagnosis <6 months.