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Table 2 Characteristics of patients with asthma classified by DNA concentration

From: Raised sputum extracellular DNA confers lung function impairment and poor symptom control in an exacerbation-susceptible phenotype of neutrophilic asthma

Characteristic Low-eDNA
(n = 95)
High-eDNA
(n = 39)
P-value
Age, years 52 (44–63) 51 (43–59) 0.57
Sex, % male 49 41 0.44
BMI, kg/m2 27.3 (24.0–29.0) 26.3 (23.8–34.4) 0.58
Smoking history % 20 27 0.37
Current smokers, % 9 10 1.0
Severe asthma, % 41 64 0.021
Severe exacerbations in last 12 months, % 49 74 0.012
ICS dose, µg 450 (250–950) 500 (450–1000) 0.026
OCS use, % 20 33 0.12
OCS dose; mg 7.5 (5–11) 12 (10–15) 0.14
Blood cell counts, 103/µl
 Eosinophils 245 (140–477) 190 (135–450) 0.56
 Neutrophils 4035 (3302–5758) 4810 (3415–6135) 0.24
Sputum cell counts
 Eosinophils, 106/ml 0.03 (0.01–0.14) 0.06 (0.01–0.24) 0.29
 Eosinophils, %* 1.5 (0.4–5.1) 2.0 (0.35–14.1) 0.87
 Neutrophils, 106/ml 0.81(0.31–1.83) 2.5 (1.0–5.8)  < 0.0001
 Neutrophils, %* 48 (30–61) 65 (40–77) 0.005
 Macrophages, 106/ml 0.56(0.36–0.93) 0.67 (0.37–1.1) 0.43
 Macrophages, %* 37 (18–56) 19 (11–34) 0.002
Sputum cell viability, % 80 (71–87) 80 (70–88) 0.93
Duration of sputum induction, min 21 (14–21) 21 (14–21) 0.30
FeNO, ppb 25 (15–46) 22 (11–35) 0.1
FEV1, % 87 (74–99) 76 (59–87) 0.002
FVC, % 109 (96–116) 104 (90–112) 0.06
FEV1/FVC, % 68 (61–73) 62 (54–72) 0.059
FEF50, % 58 (38–78) 37 (24–61) 0.004
FEF25–75, (l/s) 1.74 (1.2–2.3) 1.19 (0.64–2.0) 0.016
R20, KPa/l/s 0.32 (0.27–0.38) 0.33 (0.28–0.41) 0.29
R5, KPa/l/s 0.40 (0.35–0.50) 0.49 (0.38–0.62) 0.043
R5-20, % 32 (16–54) 51 (20–80) 0.058
X5Hz, KPa/l/s − 0.12 (− 0.18–0.09) − 0.20 (− 0.26–0.13)  < 0.001
RV, % 118 (103–132) 132 (107–164) 0.015
RV/TLC, % 36 (33–42) 41 (37–48) 0.012
sReff, % 98 (75–138) 133 (89–189) 0.016
LCI 6.1 (5.6–6.6) 6.9 (6.2–7.9)  < 0.001
  1. Data are reported in median (interquartile range)
  2. BMI body mass index, ICS inhaled corticosteroids, ICS dose fluticasone equivalent, OCS oral corticosteroids, FeNO fractional exhaled nitric oxide, FEV1 forced expiratory volume in first second, FVC forced vital capacity, FEF50% and FEF25–75 mean forced expiratory flow at 50% and between 25 and 75% of the forced vital capacity, R20 proximal airway resistance at 20 Hz, R5-20 small airway resistance (total lung resistance – large airway resistance), X5 lung reactance at 5 Hz, RV residual volume, TLC total lung capacity, sReff specific effective airway resistance, LCI lung clearance index from multiple breath washout
  3. *Sputum cell counts percentage of non-squamous cells