Asthma symptoms do not predict spirometry

BACKGROUND: Asthma is a disease characterized by variable airflow obstruction, but the measurement of airflow is often omitted in the process of diagnosis and management of the disease. OBJECTIVES: Features of asthma severity and control were examined to determine the extent to which objective measurements, including forced expiratory volume in 1 s and forced expiratory volume in 1 s/forced vital capacity, correlated with other manifestations of the disease. METHODS: Subjects were a consecutive sample of patients with asthma attending a university-based asthma clinic. All subjects underwent routine assessment using a standard questionnaire and spirometry. RESULTS: A total of 500 subjects were included in the present study, and their assessment showed that neither symptoms nor history could predict or be predicted by their measurements of lung function. CONCLUSION: Routine measurement of lung function should be performed on subjects with asthma if normal or near-normal lung function is a desired component of asthma control.