Levels of Allergy Cluster with Asthma Severity in Inner-City Children.
Sunday, March 6, 2016
South Exhibit Hall H (Convention Center)
Edward M. Zoratti, MD, FAAAAI, Rebecca A. Zabel, MS, Denise C. Babineau, PhD, Jacqueline A. Pongracic, MD FAAAAI, George T. O'Connor, MD, Robert A. Wood, MD FAAAAI, Gurjit K. Khurana Hershey, MD PhD FAAAAI, Carolyn Kercsmar, MD, Rebecca S. Gruchalla, MD PhD FAAAAI, Meyer Kattan, MD, Stephen J. Teach, MD, Samuel J. Arbes Jr., Cynthia Visness, PhD MPH, William W. Busse, MD FAAAAI, Peter J. Gergen, MD MPH, Alkis Togias, MD FAAAAI, Andrew H Liu, MD FAAAAI
Rationale:  Phenotypic characterization of asthma among urban youth is lacking.  Using unsupervised clustering techniques, we identified distinct asthma phenotypes in inner-city children who received one year of guidelines-based asthma management.

Methods:  Nine sites in the NIAID-funded Inner City Asthma Consortium enrolled 717 children aged 6-17 years with mild to severe asthma.  Data were collected at baseline and every 2 months for 1 year.  Hierarchical cluster analysis was performed in participants completing >4 follow-up visits.  Clusters were generated using 52 baseline characterization variables plus 12 longitudinal clinical variables reflecting lung function, asthma symptoms, exacerbations and  controller treatment over 1 year.  Univariate comparisons were used to determine distinguishing characteristics among clusters.

Results:  616 participants were eligible for analysis (58% male, 64% Black non-Hispanic, 29% Hispanic, 7% other).  Four distinct clusters were characterized by differences in indicators of asthma severity, including level of controller therapy, prednisone use, bronchial hyperresponsiveness and lung function. Laboratory and clinical indicators of allergy were increased in the phenotypes with higher asthma severity.  The cluster reflecting the most severe asthma included the highest proportions of self-reported eczema (77%) and food allergy (62%), along with the highest serum total IgE levels (geometric mean 763 kU/L), number of allergic sensitizations (median 15 of 20 allergens evaluated), exhaled nitric oxide levels (geometric mean 27.4 ppb), and peripheral blood eosinophil counts (median 400/microliter).

Conclusions:  Severe asthma phenotypes among  inner city children exhibit high levels of allergy.  Treatment and environmental control of allergy may be particularly important for optimal management of asthma in this population.