Clinical and physiological differences among the computed tomography diagnostic categories
| Total | UIP | Possible UIP | Inconsistent with UIP | p-value | |
| Subjects | 241 | 102 | 64 | 75 | |
| Sex male/female | 184/57 | 81/21 | 51/13 | 52/23 | 0.227 |
| Age years | 65.7±8.0 | 67.4±7.5 | 63.8±7.8* | 65.0±8.5 | 0.01 |
| Duration of illness years | 2.0±2.1 | 2.3±2.1 | 1.7±1.7 | 2.0±2.3 | 0.236 |
| Smoking ever/never | 175/66 | 82/20 | 42/22 | 51/24 | 0.065 |
| Post-walk Borg dyspnoea score# | 2.9±1.8 | 2.9±1.8 | 2.8±1.7 | 3.0±1.8 | 0.85 |
| St George's Respiratory Questionnaire total score# | 47.0±17.3 | 46.1±16.7 | 46.0±17.3 | 49.1±18.2 | 0.449 |
| 6-min walking distance m | 326.9±136.9 | 320.3±157.7 | 356.40±117.4 | 310.9±118.2 | 0.124 |
| DLCO % pred | 37.8±13.4 | 35.3±13.6 | 41.7±14.8* | 38.0±11.9 | 0.01 |
| FEV1/FVC % | 77.6±1.9 | 77.3±1.6 | 77.9±1.6 | 77.9±2.3 | 0.029 |
| FVC % pred | 63.8±16.3 | 64.8±16.0 | 65.6±17.5 | 61.0±15.3 | 0.192 |
| Total lung capacity L | 4.0±1.1 | 4.1±1.1 | 4.2±1.2 | 3.7±0.9*,¶ | 0.011 |
| History of antigen exposure | 13 (5.39) | 6 (5.88) | 4 (6.25) | 3 (4.00) | 0.491 |
| Gastro-oesophageal reflux symptoms | 161 (66.8) | 64 (62.8) | 44 (68.8) | 53 (70.7) | 0.504 |
Data are presented as n, mean±sd or n (%), unless otherwise stated. UIP: usual interstitial pneumonia; DLCO: diffusing capacity of the lung for carbon monoxide; FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity. #: higher score indicates worse function. *: p<0.05 versus UIP group; ¶: p<0.05 versus possible UIP group.