No AFL | AFL | Potentially underdiagnosed AFL | Potentially overdiagnosed AFL | |||||
(n=78 779) | (n=12 365) | (n=1056) | p versus No AFL | p versus AFL | (n=3088) | p versus No AFL | p versus AFL | |
Use of airway medication | 4.2 | 17 | 8.6 | <0.0001 | <0.0001 | 6.4 | <0.0001 | <0.0001 |
Asthma | 5.2 | 18 | 10 | <0.0001 | <0.0001 | 8.0 | <0.0001 | <0.0001 |
Allergy | 27 | 31 | 28 | 0.40 | 0.08 | 28 | 0.43 | 0.004 |
Symptoms | ||||||||
Chronic mucus hypersecretion | 7.4 | 17 | 14 | <0.0001 | 0.06 | 9.4 | <0.0001 | <0.0001 |
Dyspnoea | 30 | 44 | 39 | <0.0001 | 0.004 | 33 | 0.001 | <0.0001 |
mMRC ≥2 | 7.1 | 14 | 10 | 0.003 | 0.02 | 8.0 | 0.02 | <0.0001 |
Night-time dyspnoea | 3.2 | 6.0 | 5.3 | 0.0002 | 0.37 | 3.6 | 0.28 | <0.0001 |
Wheezing | 14 | 33 | 24 | <0.0001 | <0.0001 | 20 | <0.0001 | <0.0001 |
Cough | 11 | 22 | 18 | <0.0001 | 0.0003 | 13 | <0.0001 | <0.0001 |
Any symptom | 40 | 59 | 54 | <0.0001 | 0.001 | 46 | <0.0001 | <0.0001 |
Degree of AFL# | ||||||||
FEV1 % predicted ≥80 | 97 | 50 | 80 | <0.0001 | <0.0001 | 74 | <0.0001 | <0.0001 |
FEV1 % predicted 50–79 | 8.8 | 42 | 20 | <0.0001 | <0.0001 | 25 | <0.0001 | <0.0001 |
FEV1 % predicted 30–49 | 0.1 | 7.5 | 0.3 | 0.15 | <0.0001 | 0.6 | <0.0001 | <0.0001 |
FEV1 % predicted <30 | 0.1 | 1.0 | 0 | 0.70 | 0.001 | 0 | 0.51 | <0.0001 |
Concentration of inflammatory biomarkers in the blood | ||||||||
C-reactive protein mg·L−1 | 2.4 | 2.8 | 2.5 | 0.32 | 0.05 | 2.3 | 0.28 | <0.0001 |
Fibrinogen µmol·L−1 | 11.0 | 11.2 | 11.1 | 0.32 | 0.08 | 10.9 | 0.005 | <0.0001 |
Leucocytes ×109 per L | 7.2 | 7.6 | 7.6 | <0.0001 | 0.71 | 7.3 | 0.08 | <0.0001 |
Neutrophils ×109 per L | 4.2 | 4.5 | 4.5 | <0.0001 | 0.82 | 4.3 | 0.02 | <0.0001 |
Eosinophils ×109 per L | 0.19 | 0.21 | 0.21 | 0.001 | 0.26 | 0.20 | 0.0002 | 0.001 |
Number of acute bronchitis or pneumonia episodes in the last 10 years | ||||||||
None | 79 | 67 | 73 | <0.0001 | <0.0001 | 73 | <0.0001 | <0.0001 |
1–5 | 20 | 28 | 25 | 0.0002 | 0.02 | 25 | <0.0001 | 0.001 |
≥6 | 1.4 | 4.9 | 2.2 | 0.09 | 0.0002 | 1.7 | 0.34 | <0.0001 |
Number of visits to the general practitioner office in the last 12 months | ||||||||
None | 21 | 19 | 20 | 0.25 | 0.31 | 20 | 0.21 | 0.07 |
Once | 23 | 21 | 21 | 0.26 | 0.64 | 20 | 0.01 | 0.88 |
Twice or more | 56 | 61 | 59 | 0.05 | 0.32 | 59 | 0.009 | 0.06 |
Data are presented as % and means. Percentages are age- and sex-adjusted, obtained from logistic regression models. Mean concentrations of inflammatory biomarkers in the blood are age- and sex-adjusted, obtained from linear regression models. p-Values are obtained from Wald tests. No airflow limitation (AFL) was defined as forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) ≥0.70 and FEV1/FVC ≥lower limit of normal (LLN). Potentially underdiagnosed AFL was defined as FEV1/FVC ≥0.70 and FEV1/FVC <LLN. Potentially overdiagnosed AFL was defined as FEV1/FVC <0.70 and FEV1/FVC ≥LLN. AFL was defined as FEV1/FVC <0.70 and FEV1/FVC <LLN. GP: general practitioner; mMRC: modified Medical Research Council dyspnoea scale. #: Since FEV1 % predicted is already age- and sex-adjusted, no further adjustment was performed. p-Values are obtained from Pearson Chi-squared tests.