Auscultation of crackles at the initial clinic visit in patients according to symptoms (n=290) and lung function*
| None | Fine crackles | Coarse crackles | Both | P value† | |
| IPF, n (%) | |||||
| With no dyspnoea (MRC=1) | 0 (0.0%) | 21 (80.8%) | 2 (7.7%) | 3 (11.5%) | 0.549 |
| With dyspnoea (MRC >1) | 2 (1.9%) | 76 (73.8%) | 5 (4.9%) | 20 (19.4%) | |
| Non-IPF, n (%) | |||||
| With no dyspnoea (MRC=1) | 9 (22.5%) | 23 (57.5%) | 2 (5.0%) | 6 (15.0%) | 0.255 |
| With dyspnoea (MRC >1) | 16 (13.2%) | 75 (62.0%) | 16 (13.2%) | 14 (11.6%) | |
| IPF, n (%) | |||||
| With no cough | 0 (0.0%) | 15 (83.3%) | 1 (5.6%) | 2 (11.1%) | 0.710 |
| With cough | 2 (1.8%) | 82 (73.9%) | 6 (5.4%) | 21 (18.9%) | |
| Non-IPF, n (%) | |||||
| With no cough | 8 (20.5%) | 21 (53.9%) | 5 (12.8%) | 5 (12.8%) | 0.722 |
| With cough | 17 (13.9%) | 77 (63.1%) | 13 (10.7%) | 15 (12.3%) | |
| IPF, n (%) | |||||
| With no dyspnoea (MRC=1) or cough | 0 (0%) | 6 (66.7%) | 1 (11.1%) | 2 (22.2%) | 0.817 |
| With dyspnoea (MRC >1) or cough | 2 (1.7%) | 91 (75.8%) | 6 (5.0%) | 21 (17.5%) | |
| Non-IPF, n (%) | |||||
| With no dyspnoea (MRC=1) or cough | 4 (25.0%) | 8 (50.0%) | 1 (6.2%) | 3 (18.8%) | 0.531 |
| With dyspnoea (MRC >1) or cough | 21 (14.5%) | 90 (62.1%) | 17 (11.7%) | 17 (11.7%) | |
| IPF, n (%) | |||||
| With predicted FVC ≥80% | 2 (3.1%) | 51 (79.7%) | 2 (3.1%) | 9 (14.1%) | 0.158 |
| With predicted FVC <80% | 0 (0%) | 45 (71.5%) | 5 (7.9%) | 13 (20.6%) | |
| Non-IPF, n (%) | |||||
| With predicted FVC ≥80% | 17 (18.5%) | 55 (59.8%) | 9 (9.7%) | 11 (12%) | 0.649 |
| With predicted FVC <80% | 8 (11.8%) | 42 (61.8%) | 9 (13.2%) | 9 (13.2%) | |
| IPF, n (%) | |||||
| With predicted TLC ≥80% | 2 (3.7%) | 41 (75.9%) | 2 (3.7%) | 9 (16.7%) | 0.262 |
| With predicted TLC <80% | 0 (0%) | 55 (76.4%) | 5 (6.9%) | 12 (16.7%) | |
| Non-IPF, n (%) | |||||
| With predicted TLC ≥80% | 18 (20.2%) | 47 (52.8%) | 13 (14.6%) | 11 (12.4%) | 0.053 |
| With predicted TLC <80% | 6 (8.7%) | 49 (71.0%) | 5 (7.3%) | 9 (13.0%) | |
| IPF, n (%) | |||||
| With predicted DLco ≥80% | 1 (6.3%) | 12 (75.0%) | 1 (6.3%) | 2 (12.4%) | 0.623 |
| With predicted DLco <80% | 1 (1.0%) | 80 (76.2%) | 6 (5.7%) | 18 (17.1%) | |
| Non-IPF, n (%) | |||||
| With predicted DLco ≥80% | 5 (18.5%) | 15 (55.6%) | 4 (14.8%) | 3 (11.1%) | 0.879 |
| With predicted DLco <80% | 18 (14.9%) | 74 (61.2%) | 13 (10.7%) | 16 (13.2%) |
*Three patients were unable to perform spirometry at the time of initial visit, 6 unable to perform lung volumes and 21 unable to perform DLco.
†P value obtained by χ2 test (likelihood ratio) comparing the column proportions for fine crackles, coarse crackles, both and none.
DLco, carbon monoxide diffusing lung capacity (n=269); FVC, forced vital capacity; FVC, forced vital capacity (n=287 patients); IPF, idiopathic pulmonary fibrosis; MRC, British Medical Research Council Dyspnoea Score (1 to 5); TLC, total lung capacity (n=284).