TABLE 1

Characteristics of the study groups

Never- and ex-smokers with <10 pack-yearsNon-obstructive patients with ≥10 pack-yearsACOS: ≥10 pack-years FEV1/FVC <0.7p-value#
Subjects n1223234
Age years56.7±13.959.8±12.865.0±10.70.005
BMI kg·m−227.9 (24.3–31.2)30.6 (25.4–33.8)28.1 (24.2–30.7)0.093
Male36 (29.5)19 (59.4)24 (70.6)<0.001
Asthma duration years12.3±0.612.4±0.712.0±0.70.091
Pack-years (of ex-/current smokers)3 (1–5)
range 0–9
21 (17–31)
range 10–47
26 (15–34)
range 10–68
<0.001
Smoking status<0.001
 Never-smoker96 (78.7)00
 Ex-smoker26 (21.3)17 (53.1)25 (73.5)
 Current smoker0ƒ15 (46.9)9 (26.5)
Asthma control according to GINA<0.001
 Controlled54 (44.3)5 (15.6)5 (14.7)
 Partly controlled41 (33.6)18 (56.3)10 (29.4)
 Uncontrolled27 (22.1)9 (28.1)19 (55.9)
ICS in daily use96 (78.7)26 (81.3)27 (79.4)0.950
ICS dose per day bud eq§800 (400–1000)1000 (763–1900)800 (800–1200)0.023
LABA in daily use51 (41.8)21 (65.6)21 (61.8)0.016
LAMA, LTRA or theophylline in daily use20 (16.5)7 (21.9)8 (23.5)0.575
Use of oral steroid courses ever38 (31.7)14 (43.8)7 (21.2)0.149
≥2 oral steroid courses in 2 years16 (13.3)6 (18.8)4 (12.1)0.691
ACT score22 (20–25)21 (19–24)21 (16–23)0.025
CAT score10±714±716±7<0.001
AQ20 score3 (1–7)4 (2–7)4 (2–8)0.291
Post bronchodilator FEV1/FVC <0.7 at baseline##11 (9.0)1 (3.1)16 (47.1)¶,+<0.001
Skin-prick positive##44 (39.3)11 (35.5)5 (20.0)0.191
Continuous rhinitis44 (36.4)13 (41.9)8 (23.5)0.256
Allergic conjunctivitis or rhinitis79 (66.9)20 (62.5)15 (45.5)0.079

Data are presented as n (%), mean±sd, or median (interquartile range), unless otherwise stated. Statistically significant p-values are presented in bold. #: p-value across all groups; : as compared to group 1 (never and ex-smokers with <10 pack-years), p<0.05; +: as compared to group 2 (non-obstructive patients with ≥10 pack-years), p<0.05; ƒ: excluded, §: budesonide equivalent, of daily users, ##: at the moment of asthma diagnosis (1999–2002) [22]. ACOS: asthma–chronic obstructive pulmonary disease overlap syndrome; FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity; BMI: body mass index; GINA: Global Initiative for Asthma; ICS: inhaled corticosteroids; LABA: long-acting beta-agonists; LAMA: long-acting muscarinic antagonists; LTRA: leukotriene antagonists; ACT: Asthma Control Test; CAT: COPD Assessment Test; AQ20: Asthma Questionnaire 20.