Asthma and lower airway disease
Seasonal risk factors for asthma exacerbations among inner-city children

https://doi.org/10.1016/j.jaci.2014.12.1942Get rights and content

Background

Asthma exacerbations remain common, even in children and adolescents, despite optimal medical management. Identification of host risk factors for exacerbations is incomplete, particularly for seasonal episodes.

Objective

We sought to define host risk factors for asthma exacerbations unique to their season of occurrence.

Methods

This is a retrospective analysis of patients aged 6 to 20 years who comprised the control groups of the Asthma Control Evaluation study and the Inner City Anti-IgE Therapy for Asthma study. Univariate and multivariate models were constructed to determine whether patients' demographic and historical factors, allergic sensitization, fraction of exhaled nitric oxide values, spirometric measurements, asthma control, and treatment requirements were associated with seasonal exacerbations.

Results

The analysis included 400 patients (54.5% male; 59.0% African American; median age, 13 years). Exacerbations occurred in 37.5% of participants over the periods of observation and were most common in the fall (28.8% of participants). In univariate analysis impaired pulmonary function was significantly associated with greater odds of exacerbations for all seasons, as was an exacerbation in the previous season for all seasons except spring. In multivariate analysis exacerbation in the previous season was the strongest predictor in fall and winter, whereas a higher requirement for inhaled corticosteroids was the strongest predictor in spring and summer. The multivariate models had the best predictive power for fall exacerbations (30.5% variance attributed).

Conclusions

Among a large cohort of inner-city children with asthma, patients' risk factors for exacerbation vary by season. Thus information on individual patients might be beneficial in strategies to prevent these seasonal events.

Section snippets

Overview

This analysis examines risk factors for asthma exacerbations in 400 control group participants from 2 recent studies from the Inner-City Asthma Consortium: the Asthma Control Evaluation (ACE) study (n = 253)4 and the Inner City Anti-IgE Therapy for Asthma (ICATA) study (n = 147).18 Seasonal and year-round predictors are considered by using both univariate and multivariate analytic techniques. Of note, in both the ACE and ICATA studies, all participants (including control subjects) were given

Participants' characteristics

For more information on participants' characteristics, see Table I. The 400 participants from the ACE and ICATA study control treatment groups included in these analyses were typically low income (55.5% with income <$15,000), minority (59% black and 30% Hispanic), and overweight (median body mass index [BMI] percentile at screening, 88.8%). Their median age was 13 years. In the 6 months before study entry, 16.8% were hospitalized for asthma. At study screening, the mean Asthma Control Test

Discussion

Our analysis of exacerbations on a seasonal basis derived from the control treatment arms of the ACE4 and ICATA18 studies from the Inner-City Asthma Consortium reveals a number of important factors relevant to the identification of inner-city children at high risk for asthma exacerbations. First, our ability to predict exacerbations based on commonly used characteristics of patients varies greatly by season. In the fall these factors predict 30.5% of the variance, a highly clinically

References (34)

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This project has been funded in whole or in part with Federal funds from the National Institute of Allergy and Infectious Diseases, National Institutes of Health, Department of Health and Human Services, under contract nos. NO1-AI-25496, NO1-AI-25482, HHSN272200900052C, and HHSN272201000052I. Additional support was provided by the National Center for Research Resources, National Institutes of Health, under grants RR00052, M01RR00533, UL1 RR024982, M01RR00071, 5M01RR020359-04, 1UL1RR025771, 1UL1RR025780, 1UL1RR024156, UL1RR031988, UL1RR025741, and UL1TR000451. Lincoln Diagnostics provided the Multi-Test, and GlaxoSmithKline (GSK) provided study drug for Asthma Control Evaluation study participants. Novartis Pharmaceuticals provided study drug under a clinical trial agreement with the University of Wisconsin–Madison, Dey Pharma provided EpiPens, and SC Johnson provided household pest control for Inner City Anti-IgE Therapy for Asthma study participants. None of these companies had a role in the development or approval of the protocol, conduct of the trial, data analysis, manuscript preparation, or the decision to submit for publication.

Disclosure of potential conflict of interest: S. J. Teach has received research support from the National Institutes of Health (NIH)/National Institute of Allergy and Infectious Diseases (NIAID) and Novartis; is employed by the Children's National Health System; has received research support from the NIH/NIAID, the Kohls Foundation, the Stewart Foundation, and PCORI; and has received royalties from UpToDate. S. J. Szefler has received research support and travel support from the NIAID Inner-City Asthma Consortium; has received consultancy fees from Merck, Boehringer Ingelheim, GlaxoSmithKline, and Genentech; has received research support from GlaxoSmithKline; has received lecture fees from Merck; and has a patent with the National Heart, Lung, and Blood Institute (NHLBI) CARE Network. H. E. Mitchell and A. Calatroni has received research support from the NIH/NIAID. J. Wildfire and G. R. Bloomberg have received research support and travel support from the NIH/NIAID. C. M. Kercsmar has received research support from the NIH, is a board member for GlaxoSmithKline, and has received royalties from UpToDate. A. H. Liu has received lecture fees from Merck Sharp & Dohme and is a Data Safety Committee member for GlaxoSmithKline. M. M. Makhija has received travel support from the NIAID Inner-City Asthma Consortium. E. Matsui has received research support from the NIH, is a board member for the US Environmental Protection Agency Science Advisory Board, and is employed by Johns Hopkins University. W. Morgan has received research support and travel support from the NIAID/NIH and the University of Wisconsin-Madison; has received consultancy fees from Genentech and the Cystic Fibrosis Foundation; is employed by the University of Arizona; has received research support from AsthmaNet NIH/NHLBI, the Cystic Fibrosis Foundation, Mt Sinai College of Medicine, and the NIH/NHLBI; and has received lecture fees from the American Thoracic Society and the American College of Chest Physicians. G. O'Connor has received research support from the NIH. W. W. Busse has been supported by the NHLBI/NIH; is a board member for Merck; has received consultancy fees from Novartis, GlaxoSmithKline, Genentech, Roche, Pfizer, Boston Scientific, Circassia, ICON, AstraZeneca, Sanofi, Amgen, MedImmune, NeoStem, Takeda, and Boehringer Ingelheim; has received research support from the NIAID/NIH and the NHLBI/NIH; and has received royalties from Elsevier. P. J. Gergen declares that he has no relevant conflicts of interest.

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