Abstract
Background Treatment levels required to control asthma vary greatly across a population with asthma. The factors that contribute to variability in treatment requirements of inner-city children have not been fully elucidated. Objective We sought to identify the clinical characteristics that distinguish difficult-to-control asthma from easy-to-control asthma. Methods Asthmatic children aged 6 to 17 years underwent baseline assessment and bimonthly guideline-based management visits over 1 year. Difficult-to-control and easy-to-control asthma were defined as daily therapy with 500 μg of fluticasone or greater with or without a long-acting β-agonist versus 100 μg or less assigned on at least 4 visits. Forty-four baseline variables were used to compare the 2 groups by using univariate analyses and to identify the most relevant features of difficult-to-control asthma by using a variable selection algorithm. Nonlinear seasonal variation in longitudinal measures (symptoms, pulmonary physiology, and exacerbations) was examined by using generalized additive mixed-effects models. Results Among 619 recruited participants, 40.9% had difficult-to-control asthma, 37.5% had easy-to-control asthma, and 21.6% fell into neither group. At baseline, FEV1 bronchodilator responsiveness was the most important characteristic distinguishing difficult-to-control asthma from easy-to-control asthma. Markers of rhinitis severity and atopy were among the other major discriminating features. Over time, difficult-to-control asthma was characterized by high exacerbation rates, particularly in spring and fall; greater daytime and nighttime symptoms, especially in fall and winter; and compromised pulmonary physiology despite ongoing high-dose controller therapy. Conclusions Despite good adherence, difficult-to-control asthma showed little improvement in symptoms, exacerbations, or pulmonary physiology over the year. In addition to pulmonary physiology measures, rhinitis severity and atopy were associated with high-dose asthma controller therapy requirement.
Original language | English (US) |
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Pages (from-to) | 1030-1041 |
Number of pages | 12 |
Journal | Journal of Allergy and Clinical Immunology |
Volume | 138 |
Issue number | 4 |
DOIs | |
State | Published - Oct 1 2016 |
Keywords
- Child
- IgE
- allergen sensitization
- asthma
- asthma exacerbations
- asthma morbidity
- asthma phenotype
- asthma severity
- inner-city asthma
- pulmonary function
- rhinitis
ASJC Scopus subject areas
- Immunology and Allergy
- Immunology