Demographics and Clinical characteristics
Characteristics of the participants are summarized in Table 1 and Table E1-2. There were 20 healthy control subjects and 119 asthma patients (40 patients with EA, 36 patients with NA and 43 patients with PGA) recruited in the discovery set and 114 asthma patients (35 patients with EA, 30 patients with NA and 49 patients with PGA) recruited in the validation set. Detail demographics and clinical characteristics were described in the Online Data Supplement.
In the validation set, sputum supernatant cytokines, regarded as airway inflammatory biomarkers were assessed. Amongst the asthma phenotypes, patients with EA had the highest level of IL-5 and the lowest levels of TNF-α, IL-1β, IL-8 (all P < 0.05). However, patients with NA had the highest IL-1β and the lowest IL-5 levels (all P< 0.05) (Table 1). In the 12 month follow-up, there were 3(10%) patients with NA and 3(6.1%) PGA who were loss to follow-up. Finally, there were 108 patients with asthma (EA, n=35; NA, n=27; PGA, n=46) were included in the analysis with asthma exacerbations. As a result, there were significant difference in proportions of patients experiencing severe asthma exacerbation (EA vs NA vs PGA: 17.1% vs 37% vs 6.5%, P =0.004) and severe asthma exacerbation times (EA vs NA vs PGA: 0.29±0.75 vs 0.70±1.33 vs 0.09±0.35, P = 0.004) between these phenotypic groups (Table 1).