Table 1.
Risk factors and clinical characteristics of COPD with concomitant features of asthma and pure COPD.
| COPD (n = 5,402) | Overall COPD with concomitant features of asthma (n = 863) | Pure COPD (n = 4,539) | P-value | |
|---|---|---|---|---|
| Men, % | 3,200 (65.8%) | 505 (64.5%) | 2,695 (66.0%) | 0.793 |
| Age, years | 52.5 (1.5) | 57.1 (1.4) | 51.7 (1.6) | <0.001 |
| Body mass index, kg/m2 | 23.5 (0.2) | 23.3 (0.2) | 23.6 (0.2) | 0.236 |
| Ever smoker‡, % | 2,518 (48.8%) | 431 (50.8%) | 2,087 (48.5%) | 0.686 |
| Biomass use, % | 1,810 (38.3%) | 334 (41.5%) | 1,476 (37.8%) | 0.188 |
| Annual mean PM2.5 exposure (μg/m3) | 72.7(4.1) | 72.2(4.0) | 72.7(4.1) | 0.750 |
| Occupational exposure§, % | 1,461 (31.2%) | 290 (31.5%) | 1,171 (31.2%) | 0.953 |
| Allergic rhinitis | 567 (13.2%) | 170 (17.7%) | 397 (12.4%) | 0.097 |
| Eosinophil percentage in peripheral blood (%) | 2.8 (0.1) | 3.3 (0.3) | 2.7 (0.1) | 0.015 |
| Lung function | ||||
| Post-BD FEV1/FVC, % | 63.4 (0.6) | 58.5 (1.1) | 64.3 (0.6) | <0.001 |
| Post-BD FEV1% pred | 83.1 (1.5) | 76.4 (2.7) | 84.3 (1.5) | 0.002 |
| Short form (SF)-12 scores | ||||
| PCS scores | 50.7 (0.5) | 46.0 (0.6) | 51.5 (0.5) | <0.001 |
| MCS scores | 53.9 (0.4) | 51.7 (0.5) | 54.3 (0.4) | <0.001 |
| Comorbidities | ||||
| Hypertension | 535 (9.6%) | 124 (13.2%) | 411 (8.8%) | 0.238 |
| Coronary heart disease | 130 (2.7%) | 55 (4.8%) | 75 (2.2%) | 0.061 |
| Diabetes | 151 (2.0%) | 31 (3.8%) | 120 (1.6%) | 0.333 |
| Medication usage | ||||
| Inhaled corticosteroid | 100 (3.9%) | 75 (10.6%) | 25 (0.6%) | 0.010 |
| Inhaled bronchodilator | 146 (5.9%) | 122 (15.3%) | 24 (1.2%) | 0.004 |
| Aminophylline | 166 (19.0%) | 141 (21.4%) | 25 (7.1%) | 0.004 |
| Systemic corticosteroid | 85 (10.3%) | 71 (11.1%) | 14 (6.5%) | 0.175 |
| Exacerbation of respiratory symptoms in the preceding 12 months | ||||
| Emergency, % | 269 (4.3%) | 181 (18.8%) | 88 (1.6%) | <0.001 |
| Hospital admission, % | 145 (2.5%) | 101 (10.7%) | 44 (1.0%) | <0.001 |
Values are weighted and shown as number (%) or mean (SE). FEV1, forced expiratory volume in 1second; FVC, forced vital capacity; MCS, mental component summary; PCS, physical component summary; PM2.5, ambient particulate matter with a diameter <2.5 μm.
‡
Ever smoker was defined as having smoked equal to or >100 cigarettes in his/her lifetime.
§
Occupational exposure was defined as exposed to gas, smoke, chemical vapors or fumes in work above 3 months in his/her lifetime.