TABLE 2.
Main characteristics (mean ± SD or %) of patients studied
| Demographics and exposures | ‘Asthma’ (n = 5932) | ‘Asthma + COPD’ (n = 1396) | ‘COPD’ (n = 3898) | p‐value a |
|---|---|---|---|---|
| Age, mean, years ± SD | 52.0 ± 17.1 | 64.7 ± 10.3 | 66.6 ± 9.6 | <0.0001 |
| Male, % | 37.5 | 53.1 | 61.5 | <0.0001 |
| BMI, mean, kg/m2 ± SD | 28.0 ± 6.6 | 28.5 ± 6.4 | 27.6 ± 6.3 | <0.0001 |
| Smoking status, % | <0.0001 | |||
| Current smoker | 8.1 | 24.5 | 29.6 | |
| Former smoker | 30.2 | 63.5 | 64.0 | |
| Never smoked | 61.7 | 12.0 | 6.3 | |
| Cumulative smoking exposure, mean, pack‐years ± SD | 16.7 ± 23.3 | 36.5 ± 28.9 | 47.8 ± 40.2 | <0.0001 |
| Symptoms and clinical history | ||||
| Dyspnoea (mMRC ≥Grade 2), % | 20.8 | 43.6 | 53.2 | <0.0001 |
| Frequent productive cough, % | 2.2 | 8.5 | 6.5 | <0.0001 |
| CAAT total score, mean ± SD | 14.0 ± 8.5 | 17.2 ± 8.5 | 17.0 ± 8.3 | <0.0001 |
| SGRQ total score, mean ± SD | 29.8 ± 20.9 | 39.9 ± 22.1 | 41.5 ± 21.8 | <0.0001 |
| Physician‐reported exacerbations in the past 12 months, mean ± SD | 0.7 ± 1.5 | 1.0 ± 1.8 | 0.6 ± 1.3 | <0.0001 |
| ≥1 exacerbation, % | 34.1 | 47.0 | 35.0 | <0.0001 |
| ≥1 hospital admission, % | 3.7 | 9.0 | 10.4 | <0.0001 |
| History of pneumonia, % | 3.5 | 7.2 | 7.4 | <0.0001 |
| Lung function | ||||
| Post‐bronchodilator FEV1/FVC, mean ± SD | 74.4 ± 11.8 | 59.6 ± 14.7 | 56.7 ± 16.2 | <0.0001 |
| Post‐bronchodilator FEV1/FVC <0.70, % | 28.3 | 73.5 | 74.9 | <0.0001 |
| Post‐bronchodilator FEV1% predicted, mean ± SD | 86.3 ± 20.3 | 68.3 ± 21.5 | 61.6 ± 23.0 | <0.0001 |
| Treatments | ||||
| Short‐acting bronchodilator only (±add‐on), % | 8.5 | 10.8 | 23.2 | <0.0001 |
| Inhaled steroids maintenance, any combination, % | 88.6 | 83.8 | 55.9 | <0.0001 |
| Triple therapy (ICS + LAMA + LABA), % | 13.7 | 48.7 | 36.2 | <0.0001 |
| Leukotrienes or methylxanthine, % | 30.7 | 26.4 | 9.2 | <0.0001 |
| Maintenance oral corticosteroids, % | 3.9 | 3.9 | 1.9 | <0.0001 |
| Biologic treatment, % | 9.8 | 4.2 | 0.1 | <0.0001 |
| Biomarkers | ||||
| Blood leucocytes ×109/L, mean ± SD | 7.1 ± 2.1 | 7.6 ± 2.2 | 7.6 ± 2.1 | <0.0001 |
| Blood neutrophils ×109/L, mean ± SD | 4.4 ± 1.8 | 4.9 ± 2.0 | 5.0 ± 1.9 | <0.0001 |
| Blood lymphocytes ×109/L, mean ± SD | 2.0 ± 0.6 | 2.0 ± 0.7 | 2.0 ± 0.7 | 0.8206 |
| Blood eosinophils/μl, mean ± SD | 222.8 ± 189.8 | 212.4 ± 179.2 | 182.9 ± 127.1 | <0.0001 |
| Platelets ×109/L, mean ± SD | 261.4 ± 72.4 | 264.6 ± 78.9 | 250.3 ± 80.2 | <0.0001 |
| FeNO, ppb, mean ± SD | 32.3 ± 30.7 | 24.1 ± 23.8 | 19.9 ± 17.9 | <0.0001 |
| Th2, % | <0.0001 | |||
| Low | 10.1 | 14.1 | 15.0 | |
| Medium | 57.4 | 60.0 | 67.4 | |
| High | 32.5 | 25.9 | 17.6 | |
Abbreviations: ANOVA, analysis of variance; CAAT, Chronic Airways Assessment Test; COPD, chronic obstructive pulmonary disease; FeNO, fractional exhaled nitric oxide; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; ICS, inhaled corticosteroids; LABA, long‐acting β2‐agonist; LAMA, long‐acting muscarinic antagonist; mMRC, modified Medical Research Council; ppb, parts per billion; SGRQ, St George's Respiratory Questionnaire; Th2, type‐2 airway inflammation; Th2‐high, ≥300 blood eosinophils/μl ± FeNO ≥50 ppb; Th2‐low, <100 blood eosinophils/μl + FeNO <20 ppb; Th2‐medium, neither Th2‐low nor Th2‐high.
p‐values are based on the chi‐square test for categorical variables and ANOVA for continuous variables.