Persistent Airflow Obstruction in Young Adult Asthma Patients

Background: Lung function determined by spirometry and the severity of dyspnea correlate weakly in asthma patients. We attempted to determine the risk factors in asthma patients having persistent airway obstruction despite of having only mild subjective symptoms, and to examine the possibility of improving FEV1 by treating asthma on the basis of the bronchodilator change in FEV1. Methods: We examined asthma patients in their 20s and who visited Sagamihara National Hospital for the first time over a period of four years, by reviewing their clinical records. They underwent tests on the bronchodilator change in FEV1 and a test of airway hyperresponsiveness to histamine dihydrochloride. Results: One hundred thirty-eight subjects (mean age, 25.6 years; 51 males, 87 females; current smoking, 30.4%; history of childhood asthma, 48.6%) were enrolled. Among them, 18.8% (26/138) showed persistent airway obstruction (postbronchodilator FEV1/FVC (%)