The relationship of the bronchodilator response phenotype to poor asthma control in children with normal spirometry

Abstract

Objective: To determine the relationship of poor asthma control to bronchodilator response (BDR) phenotypes in children with normal spirometry.

Study design: Children with asthma were assessed for clinical indexes of poorly controlled asthma. Pre- and post-bronchodilator spirometry were performed, and the percent BDR was determined. Multivariate logistic regression assessed the relationship of the clinical indices to BDR at ≥ 8%, ≥ 10%, and ≥ 12% BDR thresholds.

Results: There were 510 controller naïve children and 169 on controller medication. In the controller naïve population the mean age (± 1 SD) was 9.5 (3.4); 57.1% were male, 85.7% Hispanic. Demographics were similar in both populations. In the adjusted profile, significant clinical relationships were found particularly to positive BDR phenotypes ≥ 10% and ≥ 12% versus negative responses including younger age, (OR 2.0, 2.5; P < .05), atopy (OR 1.9, 2.6; P < .01), nocturnal symptoms in females (OR 3.4, 3.8; P < .01); β₂ agonist use (OR 1.7, 2.8; P < .01); and exercise limitation (OR 2.2, 2.5; P < .01) only in the controller naïve population.

Conclusions: The BDR phenotype ≥ 10% is significantly related to poor asthma control, providing a potentially useful objective tool in controller naïve children even when the pre-bronchodilator spirometry result is normal.

Conflict of interest statement

Conflict of interest: none real or perceived

Copyright © 2011 Mosby, Inc. All rights reserved.

Figures

Figure 1

Comparison of poor asthma control factors in controller naïve with on controller subset. Controller therapy status significantly impacts relationship between night symptoms, beta2-agonist use, and school days missed on likelihood of positive BDR at one or more threshold levels, unadjusted for other factors (p<.05). Non-significant subset differences were found for the following factors: atopy, family history, day symptoms, exercise limitations, steroid bursts, exacerbations, and emergency department visits/hospitalizations. View non-significance with caution due to limited number of patients on controller therapy at baseline.