Demographic and clinical characteristics
Overall, 21 patients with mild asthma, 36 with moderate asthma, 47 with
severe asthma and 31 control subjects were included in Study 1. The
gender distribution, age, body-mass index and BSA were comparable (allP >0.05, Table 1 ). The difference in atopic
status, sputum and peripheral blood eosinophil counts was unremarkable
among asthmatic patients with varying severity (allP >0.05). Patients with severe asthma had a longer
disease duration than those with mild asthma. Furthermore, compared with
patients with mild asthma and control subjects, patients with
moderate-to-severe asthma had markedly lower percentage predicted value
of forced expiratory volume in one second (FEV1) and the
ratio between FEV1 and forced vital capacity (FVC). The
percentage predicted of FEV1 and maximal mid-expiratory
flow (MMEF) was significantly lower in patients with mild asthma than in
control subjects (all P <0.05). The magnitude of
abnormality of IOS parameters was greater in patients with asthma than
in control subjects (Table E1 ). Patients with severe asthma had
significantly higher R5,
R5-R20, X5 and
Z5 compared with those with moderate asthma (allP <0.05). The magnitudes of abnormality of Fres,
R5, R5-R20,
X5, AX and Z5 were markedly higher in
patients with severe asthma than those with mild asthma (allP <0.05).
In Study 2, we recruited 16 patients with moderate asthma and 16 with
severe asthma. The baseline clinical characteristics of patients with
moderate-to-severe asthma in Study 1 did not differ from those in Study
2 (Table E2 ) .