Baseline characteristics
Clinical data from 692 adults were ultimately included. Bronchial provocation tests were positive in 170 patients and negative in 522 patients. Baseline demographics categorized by bronchial provocation test positivity are shown in Table 1. There were no significant differences in age, sex, smoking history, or body mass index (BMI) between the 2 groups. Subjects with BHR had lower FEV1, FEV1/FVC, and FEV3/FVC (P ≤ .001 for all). All FEF values, alone or as ratios of their predicted value to that of FEV1 predicted value, were significantly lower in subjects with BHR than without BHR (P < .001 for all). Small-airway dysfunction was identified in 104 patients with BHR (61.17%)and 132 patients without BHR (25.29%) (P < .001).
Significantly higher levels of IOS variables (R5-R20, X5, and Fres) were observed in the BHR group (P < .001 for all). Furthermore, FENO values, EOS counts, and EOS% were also dramatically higher in the BHR group (P< .001 for all) (Table 1).
Mean values of FEV1, FEV1/FVC, FEF50%, FEF75% and FEF25%-75% were lower in subjects with chest tightness (n = 75) compared with those without this symptom (P = .009, .008, .003, < .001, and .002, respectively). FENO values, EOS counts, and EOS% values were higher in subjects with than without chest tightness (P = .012, .001, .003, and .014, respectively).