The objective of this study was to define the bronchodilator response (BDR) cutoff point that best identified asthma to determine the frequency of abnormal spirometry results across severity. 347 children with asthma and 51 children without asthma, aged 4 to 17 years, who met entry criteria for spirometry were identified. The mean BDR in asthmatics was 8.6% compared with 2.2% for non-asthmatics. A BDR ?9% best differentiated these populations with a sensitivity rate of 42.5% and a specificity rate of 86.3%. Abnormal spirometry results, defined as a BDR ?9%, a forced expiratory volume in 1 second <80% predicted, or both, ranged from 44.4% for mild intermittent bronchial asthma to 57.0% for severe persistent bronchial asthma. The authors conclude that spirometric criteria that include BDR can potentially identify children who have clinically mild asthma and might benefit from controller therapy.
The Journal of Pediatrics, 2007, 151(5), 457-462