Characteristics of participants with persistent cough and those diagnosed with chronic obstructive pulmonary disease (COPD), asthma, and neither of these.
| Characteristic | Total, n = 353 | COPD, n = 102a | Asthma, n = 23 | No COPD or asthma, n = 228 |
|---|---|---|---|---|
| History and physical examination (day 1) | ||||
| Age in years, mean (SD) | 63 (9) | 65 (10) | 61 (8) | 62 (8) |
| Male sex, % | 45 | 61 | 44 | 38 |
| Current smoking, % | 26 | 50 | 22 | 16 |
| Cardiovascular disease,b % | 19 | 34 | 9 | 14 |
| Allergy for pollen or house dust mite,b % | 13 | 8 | 35 | 13 |
| Duration of cough in days, mean (median, SD) | 93 (40, 169) | 84 (30, 181) | 178 (90, 230) | 88 (40, 154) |
| Previous GP consultation for cough, % | 43 | 30 | 48 | 48 |
| Complaints of phlegm, % | 75 | 83 | 91 | 70 |
| Complaints of wheezing, % | 47 | 62 | 39 | 42 |
| MRC dyspnoea score,c mean (SD) | 3 (1.4) | 3.1 (1.4) | 2.9 (1.1) | 3.0 (1.5) |
| Asthma in first-degree family member, % | 24 | 22 | 26 | 24 |
| COPD in first-degree family member, % | 39 | 46 | 48 | 34 |
| Body mass index (kg/m2), mean (SD) | 28 (5) | 27 (5) | 29 (5) | 29 (5) |
| Spirometry resultsd day 90 | ||||
| FEV1 in litres, mean (SD) | 2.8 (0.8) | 2.4 (0.7) | 3.0 (0.8) | 2.9 (0.8) |
| FEV1 % predicted, mean (SD) | 101 (18) | 84 (20) | 107 (13) | 107 (16) |
| FEV1 % after bronchodilation, mean (SD) | 6 (12) | 8 (12) | 10 (8) | 4 (12) |
| FVC in litres, mean (SD) | 3.7 (1.0) | 3.7 (1.0) | 4.0 (1.1) | 3.6 (1.0) |
| FVC % predicted, mean (SD) | 110 (18) | 107 (19) | 113 (15) | 111 (17) |
| FEV1/FVC mean (SD) | 0.73 (0.1) | 0.62 (0.1) | 0.76 (0.1) | 0.78 (0.1) |
↵a 14 of the 102 patients with COPD also had asthma, not included in the n = 23 patients with asthma.
↵b Physician diagnosed.
↵c Medical Research Council (MRC) dyspnoea score: 1 = ‘never’; 2 = ‘only during strenuous exercise’; 3 = ‘walking fast or uphill’; 4 = ‘walking with people of same age’; 5 = ‘walking flat’; 6 = ‘in rest’.
↵d Post-bronchodilator results. FEV1 = forced expiratory volume in 1 second. FVC = forced vital capacity.