| COPD | COPD and asthma | p-value | |
| Subjects n | 3120 | 450 | |
| Age years | 64.0±8.4 | 60.0±8.7 | <0.001 |
| Females | 1335 (42.8) | 252 (56) | <0.001 |
| African–American | 627 (20.1) | 167 (37.1) | <0.001 |
| Pack-years | 54.2±27.8 | 45.7±25.1 | <0.001 |
| BMI kg·m−2 | 27.9±6.1 | 28.8±6.9 | 0.006 |
| FEV1 L | 1.45±0.63 | 1.40±0.62 | 0.16 |
| FEV1 % predicted | 50.3±18.0 | 50.3±17.9 | 0.95 |
| FEV1/FVC | 0.49±0.13 | 0.51±0.13 | 0.02 |
| Emphysema | 13.54±12.95 | 9.93±11.5 | <0.001 |
| Bronchodilator responsiveness | 1120 (36.13) | 177 (39.42) | 0.19 |
| Absolute BDR L | 0.09±0.16 | 0.11±0.16 | 0.11 |
Data are presented as mean±sd or n (%), unless otherwise stated. COPD: chronic obstructive pulmonary disease; BMI: body mass index; FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity; BDR: bronchodilator response (>200 mL and 12% change in FEV1).