The association between transfer coefficient of the lung and the risk of exacerbation in asthma-COPD overlap: an observational cohort study

Table 1 Mean values or frequencies of demographic and clinical characteristics

Variables	Mean values (standard deviation), median values (interquartile range), or frequencies
Male gender (%)	81.9
Age (years)	69.8 (9.1)
Body surface area (m²)	1.66 (0.19)
Body mass index (kg/m²)	22.7 (3.4)
Smoking history (pack-year)	39.0 (20.0–50.0)
Smoking history ≥ 10 pack-years (%)	92.6
Emphysema (%)	68.1
Blood eosinophil levels (%)	5.2 (2.8–8.9)
Blood eosinophil counts (/µl)	351 (150–538)
Eosinophilic component (%)	59.6
FeNO (ppb)	31.5 (19.0–59.0)
High FeNO (%)	46.8
Total IgE levels (IU/ml)	406 (119–868)
Positive levels for total IgE and/or IgE specific to perennial inhalant antigens (%)	79.8
Bronchial reversibility (%)	19.1
FEV₁ (l)	1.64 (0.67)
FEV₁ per predicted
Disease severity
Mild (%)	28.7
Moderate (%)	42.6
Severe/very severe (%)	28.7
≥ 1 exacerbation in the previous year (%)	42.6
Inhaled long-acting bronchodilator use (%)	72.3
Inhaled corticosteroid use (%)	68.1
Systemic corticosteroid use (%)	8.5

Age, body surface area, body mass index, and FEV₁ are given as the mean with standard deviations. Smoking history, blood eosinophil levels and counts, FeNO, and total IgE levels are shown as the median with an interquartile range because of their skewed distributions. Other variables are given as the number of cases and percentages. The eosinophilic component was defined as blood eosinophil ≥ 5% and/or ≥ 300/µl. High FeNO was defined as > 35 ppb. Bronchial reversibility was defined as ≥ 12% and ≥ 200 ml reversibility in post-bronchodilator FEV₁. Positive levels for total IgE were defined as > 170 IU/ml. Inhaled long-acting bronchodilator use referred to the use of long-acting β₂ agonists and/or long-acting muscarinic antagonists
BMI, body mass index; FeNO, fractional exhaled nitric oxide; ppb, parts per billion; IgE, immunoglobulin E; FEV₁, forced expiratory volume in 1 s

ISSN: 1471-2466