Description of demographic and clinical variables in subjects with and without COPD
| Non-COPD (post FEV1/FVC≥0.7) and no DDX asthma/emphysema/ chronic bronchitis/COPD | All COPD (post FEV1/FVC <0.7) | |||
|---|---|---|---|---|
| GOLD stage 1 (post FEV1/FVC<0.7 and %pred FEV1≥0.8) | GOLD stage 2 (post FEV1/FVC <0.7 and 0.5 ≤%pred FEV1<0.8) | Gold stage 3–4 (post FEV1/FVC<0.7 and %pred FEV1<0.5) | ||
| N=3379 | N=465 | N=315 | N=58 | |
| Demographics | ||||
| Age, mean (SD) | 56.4 (10.6) | 64.31 (11.6)* | 64.08 (11.2)* | 65.97 (9.1)* |
| Men, n (%) | 1470 (43.5%) | 246 (52.9%)* | 156 (49.5%)* | 23 (39.7%) |
| BMI, mean (SD) | 27.6 (5.6) | 26.97 (4.5) | 28.19 (5.8) | 29.47 (7.5) |
| Education, mean (SD) | 15.6 (3.4) | 15.11 (3.9) * | 14.23 (3.8)* | 12.95 (4.0)* |
| Smoking of cigarettes | ||||
| Smoking status, n (%) | ||||
| Never | 1711 (50.6%) | 175 (37.6%)* | 76 (24.1%)* | 8 (13.8%)* |
| Former | 1299 (38.4%) | 211 (45.4%)* | 151 (47.9%)* | 27 (46.6%) |
| Current | 369 (10.9%) | 79 (17.0%)* | 88 (27.9%)* | 23 (39.7%)* |
| Pack years of cigarettes, mean (SD) | 19.8 (19.3) | 29.96 (22.5)* | 37.31 (27.4)* | 49.42 (30.5)* |
| Passive smoking, n (%) | 277 (8.2%) | 66 (14.2%)* | 40 (12.7%)* | 10 (17.2%)* |
| Exacerbation history, n (%) | ||||
| Ever exacerbation | 477 (14.1%) | 94 (20.2%)* | 96 (30.5%)* | 31 (53.5%)* |
| Exacerbation in the past 1 year | 130 (3.9%) | 20 (4.3%) | 32 (10.2%)* | 17 (29.3%)* |
| Exacerbation need to see a doctor in the past 1 year | 89 (2.6%) | 11 (2.4%) | 23 (7.3%)* | 9 (15.5%)* |
| Exacerbation need to be hospitalised overnight in the past 1 year | 11 (0.3%) | 2(0.4%) | 7(2.2%)* | 2 (3.5%)* |
| Respiratory symptoms, n (%) | ||||
| Chronic cough | 283 (8.4%) | 68 (14.6%)* | 89 (28.3%)* | 30 (51.7%)* |
| Chronic phlegm | 198 (5.9%) | 58 (12.5%)* | 75 (23.8%)* | 29 (50%)* |
| Wheezing | 645 (19.1%) | 155 (33.3%)* | 177 (56.2%)* | 46 (79.3%)* |
| Breathlessness | 658 (20.6%) | 114 (26.7%)* | 136 (49.3%)* | 40 (83.3%)* |
| Disease and comorbidities, n (%) | ||||
| DDX asthma | 0 | 102 (21.9%)* | 96 (30.5%)* | 29 (50%)* |
| DDX emphysema/COPD/chronic bronchitis | 0 | 52 (11.2%)* | 82 (26.0%)* | 34 (58.6%)* |
| Comorbidities† | 1089 (32.2%) | 216 (46.5%)* | 152 (48.3%)* | 35 (60.3%)* |
| Childhood hospitalisation for breathing problems | 136 (4.0%) | 31 (6.7%)* | 38 (12.1%)* | 3 (5.2%) |
| Use of respiratory medications, n (%) | 818 (24.2%) | 162 (34.8%)* | 148 (47.0%)* | 47 (81.0%)* |
| Prescribed medication, (%) | (9.1%) | (25.0%) | (39.9%) | (79.3%) |
| Bronchodilator‡ | (3.3%) | (17.6%) | (35.2%) | (74.1%) |
| Inhaled steroid‡ | (7.5%) | (18.9%) | (29.8%) | (69.0%) |
| Oral steroid‡ | (0.2%) | (0.2%) | (1.6%) | (1.7%) |
| Anti-inflammatory (other)‡ | (0.1%) | (1.1%) | (1.6%) | (1.7%) |
| OTC§ medication | (15.1%) | (9.8%) | (7.1%) | (1.7%) |
| Quality of life, n (%) | ||||
| Self-perceived health status: fair or poor | 251 (7.4%) | 41 (8.8%) | 51 (16.2%)* | 23 (39.7%)* |
| Pulmonary function | ||||
| % Δ FEV1i¶>12%, n (%) | 116 (3.43) | 56 (12.0%)* | 84 (26.7%)* | 25 (43.1%)* |
| Post-BD FVC (L), mean (SD) | 3.8 (1.0) | 4.14 (1.1)* | 3.28 (0.9)* | 2.40 (0.8)* |
| Post-BD FEV1 (L), mean (SD) | 3.0 (0.8) | 2.71 (0.7)* | 1.96 (0.6)* | 1.04 (0.3)* |
| Post-BD FEV1/FVC, mean (SD) | 79.2 (4.7) | 65.54 (4.1)* | 60.01 (7.3)* | 44.66 (11.1)* |
*Significant p values are indicated by asterisks (p<0.05); non-COPD subgroup is the reference for all comparisons.
†Comorbidities include heart disease, hypertension, diabetes, and stroke.
‡Some subjects may appear in more than one subgroup as they may be taking more than one prescribed medication for their respiratory symptoms.
§Includes antihistamine, decongestant and antitussives.
¶%ΔFEV1i=(post FEV1 – pre FEV1)/pre FEV1.
BD, bronchodilator; BMI, body mass index; DDX, self-reported doctor's diagnosis; GOLD, Global Initiative for Obstructive Lung Disease.