Value of the bronchodilator response in assessing controller naïve asthmatic children

Abstract

Objective: To define the bronchodilator response (BDR) cutoff point that best identified asthma to determine the frequency of abnormal spirometry results across severity.

Study design: Controller naïve children were evaluated with clinical criteria alone to establish a diagnosis of asthma and severity classification, then compared with the BDR, which was calculated as the percent change from the initial forced expiratory volume in 1 second. Receiver operator characteristic analysis determined the cutoff point for asthma diagnosis that gave the best combination of sensitivity and specificity.

Results: Children with asthma (n = 346) 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% (95% CI, 7.5-9.8), compared with 2.2% (95% CI, 0.2-4.3) for non-asthmatics (P < .001). A BDR > or = 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 > or = 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.

Conclusion: Spirometric criteria that include BDR can potentially identify children who have clinically mild asthma and might benefit from controller therapy.