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 standard deviation) 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); β(2) 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.
Authors: Galant SP, Morphew T, Newcomb RL, Hioe K, Guijon O, Liao O
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