Table 2. Baseline characteristics of the patient population per diagnosis.
| Variable | COPD, n=2,031 | Overlap syndrome, n=787 | Asthma, n=5,223 |
|---|---|---|---|
| Gender and age | n (%) | n (%) | n (%) |
| Male | 1,190 (58.6) | 388 (49.3) | 2,007 (38.4) |
| Self-reported ⩾1 allergy | 243 (12.0) | 312 (39.6) | 2,658 (50.9) |
| Mean (s.d.) | Mean (s.d.) | Mean (s.d.) | |
| Age, years | 66.6 (10.8) | 60.6 (12.3) | 43.6 (18.7) |
| Age of onset, years | 52.2 (19.6) | 33.6 (23.1) | 22.3 (19.6) |
| Body mass index (kg/m2) | 26.6 (4.8) | 27.1 (4.9) | 26.7 (6.0) |
| Exacerbations in the last 12 months | 0.7 (1.1) | 0.9 (1.2) | 0.8 (1.2) |
|
Lung function post bronchodilator, mean (s.d.)
| |||
| FEV1 (L) | 2.0 (0.7) | 2.3 (0.7) | 3.1 (0.9) |
| FEV1% predicted | 69.0 (18.1) | 76.0 (15.5) | 94.6 (15.1) |
| FVC (L) | 3.6 (1.0) | 3.7 (1.1) | 4.0 (1.1) |
| FVC % predicted | 98.6 (18.4) | 102.1 (17.2) | 101.1 (16.3) |
| FEV1/FVC | 56.0 (11.2) | 61.0 (9.5) | 79.3 (8.8) |
| Reversibilitya | 6.4 (7.9) | 11.2 (10.0) | 6.7 (7.6) |
|
Positive BDT
b
adults, n (%)
| |||
| Post FEV1/FVC<70% | 198 (99.0) | 236 (91.5) | 204 (25.0)c |
| Post FEV1/FVC=70–80% | 2 (1.0) | 22 (8.5) | 358 (43.8) |
| Post FEV1/FVC=80–90% | 214(26.2) | ||
| Post FEV1/FVC⩾90% | 40 (4.9) | ||
| Total | 200 (10.7) | 258 (34.8) | 817 (16.6) |
|
Inhalation technique
a
, n (%)
| |||
| Correct | 325 (36.1) | 205 (36.5) | 1,434 (38.0) |
| Incorrect | 576 (63.9) | 357 (63.5) | 2,339 (62.0) |
|
Smoking history (age⩾18 years), n (%)
| |||
| Smoking history missing | 8 (0.4) | 0 (0.0) | 17 (0.4) |
| Never smoked | 70 (3.4) | 54 (6.9) | 2,041 (43.4) |
| Quit ⩾12 months ago | 948 (46.7) | 378 (48.0) | 1,628 (34.6) |
| Current smoker | 1,005 (49.5) | 355 (45.1) | 1,014 (21.6) |
| Males | 517 (51.4) | 151 (42.5) | 383 (37.8) |
| Males motivated to quit | 304 (58.8) | 89 (58.9) | 231 (60.3) |
| Females | 475 (47.3) | 197 (55.5) | 614 (60.6) |
| Females motivated to quit | 295 (62.1) | 112 (56.8) | 407 (66.3) |
Abbreviations: BDT, bronchodilator test; COPD, chronic obstructive pulmonary disease; FEV1, forced expiratory volume in one second; FVC, forced vital capacity.
a
Increase in FEV1 pre bronchodilator compared with FEV1 post bronchodilator.
b
Positive bronchodilator response test defined as a reversible lung function of ⩾200 ml and ⩾12% increase in FEV1 pre bronchodilator compared with FEV1 post bronchodilator.
c
Adult asthma patients (male: 59%, mean age: 52 years, 19% current smokers) with obstruction before and after bronchodilator.