Abstract
PURPOSE: Sensitively assessing bronchial reversibility by spirometry is difficult in patients with serious airflow limitation and the elderly. Some patients cannot exhale for ≥6 s to achieve FVC testing criteria. The aim of this study was to assess if FEV(3) could be a more sensitive and an acceptable surrogate for evaluating bronchial reversibility in such patients. PATIENTS AND METHODS: Subjects who had undergone pulmonary function examination in Beijing hospital from July 2003 to April 2015 were included in the study. Patients with FEV(1)<50% of the predicted value were classified as the severely lung function-impaired group. Correlation between the severity of lung function impairment and changes in FEV(1), FEV(3) and FVC in response to a bronchodilator was estimated. RESULTS: A total of 7745 tests on elderly subjects with a median age of 71 years were reviewed. The severely lung function-impaired group of 1728 accounted for 22.3% of the total number of subjects. There were significantly more patients in the severely lung function-impaired group who exhibited positive response in FEV(3) or FVC and negative response in FEV(1) after bronchodilator test (FEV(1) negative response but FVC positive response, χ2=626.97, P<0.001; FEV(1) negative response but FEV(3) positive response, χ2=372.83, P<0.001). With the progressive increase in lung function impairment, ΔFEV(1) increased and then declined, while ΔFVC and ΔFEV(3) increased progressively. Changes in FEV(3) or FVC significantly exceeded the change in FEV(1) in the severely lung function-impaired groups (P<0.001). CONCLUSION: In elderly subjects, especially those with severe lung function impairment, FEV(3) combined with FVC is a more effective and sensitive primary clinical outcome measure to detect bronchial reversibility. In subjects who cannot complete ≥6 s forced expiration and whose FVC is unreliable, FEV(3) combined with FEV(1) might be clinically more valuable in detecting bronchial reversibility.