Determinants of bronchodilator responsiveness in patients with controlled asthma.

Short-term bronchodilator responsiveness to an inhaled β 2 adrenergic agonist was assessed by changes in forced expiratory volume in 1 second (FEV1) in nonsmoking adults with controlled asthma (mild disease, 20 patients; moderate disease, 20 patients; severe disease, 18 patients). Responsiveness correlated significantly with age and with percent of predicted FEV1 (%FEV1) except in patients with severe asthma, who showed significantly less responsiveness than others. Thus, responsiveness is closely associated with degree of airflow limitation in patients with controlled asthma and is significantly influenced by severity of disease and by aging.