Table 2. Baseline Characteristics for LEUVEN participants stratified for the clinical impact of airflow obstruction.
| Asymptomatic smokers | Ambulatory COPD patients | End-stage COPD patients | p-value | |
| (n = 366) | (n = 394) | (n = 123) | ||
| Demographics | ||||
| Age, mean (SD), yr | 62.3 (5.71) | 67.6 (8.67) | 57.2 (4.69) | <0.001 |
| Male sex, no. (%) | 286 (78.1) | 305 (77.4) | 62 (50.4) | <0.001 |
| Height, mean (SD), cm | 172.0 (8.9) | 168.6 (8.4) | 165.0 (8.5) | <0.001 |
| Smoking | ||||
| Pack-years history, mean (SD), yr | 45.8 (21.8) | 52.5 (27.3) | 35.5 (19.8) | <0.001 |
| Current smokers, no. (%) | 203 (55.8) | 157 (40.5) | 5 (15.6) | <0.001 |
| Smoked years, mean (SD), yr | 40.6 (7.0) | 43.2 (10.4) | 36.1 (8.2) | <0.001 |
| Years quit smokers, median (25th–75th percentiles) | 0.0 (0.0–7.0) | 2.0 (0.0–9.0) | 3.0 (1.0–6.0) | <0.001 |
| Pulmonary function tests, mean (SD) | ||||
| FEV1, L | 2.91 (0.74) | 1.38 (0.63) | 0.70 (0.30) | <0.001 |
| FEV1, % predicted | 96.4 (18.3) | 49.3 (20.1) | 25.5 (9.9) | <0.001 |
| FEV1/FVC ratio | 0.70 (0.09) | 0.45 (0.13) | 0.33 (0.08) | <0.001 |
| COPD severity, no. (%) | ||||
| No Obstruction | 218 (59.6) | 11 (2.8) | 0 (0) | <0.001 |
| GOLD class I | 96 (26.2) | 27 (6.9) | 1 (0.8) | |
| GOLD class II | 46 (12.6) | 134 (34.0) | 3 (2. 4) | |
| GOLD class III | 6 (1.6) | 157 (39.8) | 25 (20.3) | |
| GOLD class IV | 0 (0) | 65 (16.5) | 94 (76.4) |
Abbreviations are the same as in Table 1. Percentages are column percentages. The 366 asymptomatic smokers are population-based participants of the Dutch-Belgian lung cancer screening trial (NELSON). None of them were previously diagnosed with COPD. However, 148 subjects (40.4%) were found to have an obstructive lung function (based on FEV1/FVC<0.70) at inclusion. Eleven subjects (2%), that were followed-up at the outpatient clinic because of symptoms compatible with COPD, did not fulfill the criterion of COPD (FEV1/FVC>0.70). Five patients with end-stage COPD were not actively listed for lung transplantation because of their current smoking status at inclusion.