Abstract
INTRODUCTION: Dynamic hyperinflation (DH) is sometimes observed and is associated with impaired daily life activities of asthma. We assessed the relationship between DH and asthma biomarkers (blood eosinophil, fractional exhaled nitric oxide (F (eNO)) and serum periostin) in patients with asthma. METHODS: Fifty patients with stable asthma were prospectively recruited and underwent blood test, F (eNO) measurement, spirometry and metronome-paced tachypnoea (MPT) test to assess DH. In MPT tests, inspiratory capacity (IC) was measured at baseline and after 30 s of MPT with breathing frequencies of 20, 30 and 40 breaths·min(-1). DH was assessed by the decline of IC from baseline, and maximal IC reduction ≥10% was considered as positive DH. RESULTS: Thirty patients (60%) showed positive DH. Patients with positive DH showed higher serum periostin levels (107.0±30.7 ng·mL(-1)) than patients with negative DH (89.7±23.7) (p=0.04). Patients in Global Initiative for Asthma treatment steps 4-5 (n=19) showed higher serum periostin levels (p=0.01) and more severe IC reduction after MPT (p<0.0001) than patients in steps 1-3 (n=31). Maximal IC reduction after MPT was significantly correlated with asthma control test score (r=-0.28, p=0.05), forced expiratory volume in 1 s (r=-0.56, p<0.0001), and serum periostin levels (r=0.41, p=0.003). CONCLUSION: Serum periostin may have the possibility to reflect DH in patients with stable asthma.