title: Distinguishing characteristics of difficult-to-control asthma in inner-city children and adolescents.
abstract: 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.
  
  
  
  We sought to identify the clinical characteristics that distinguish difficult-to-control asthma from easy-to-control asthma.
  
  
  
  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.
  
  
  
  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, FEV1bronchodilator 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.
  
  
  
  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.
authors.affiliation: Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, Ill. Electronic address: jpongracic@luriechildrens.org.
authors.forename: Jacqueline A
authors.initials: JA
authors.lastname: Pongracic
authors.affiliation: Rho Federal Systems Division, Chapel Hill, NC.
authors.forename: Rebecca Z
authors.initials: RZ
authors.lastname: Krouse
authors.affiliation: Rho Federal Systems Division, Chapel Hill, NC.
authors.forename: Denise C
authors.initials: DC
authors.lastname: Babineau
authors.affiliation: Henry Ford Health System, Detroit, Mich.
authors.forename: Edward M
authors.initials: EM
authors.lastname: Zoratti
authors.affiliation: Boston University School of Medicine, Boston, Mass.
authors.forename: Robyn T
authors.initials: RT
authors.lastname: Cohen
authors.affiliation: Johns Hopkins University School of Medicine, Baltimore, Md.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Wood
authors.affiliation: Cincinnati Children's Hospital, Cincinnati, Ohio.
authors.forename: Gurjit K
authors.initials: GK
authors.lastname: Khurana Hershey
authors.affiliation: Cincinnati Children's Hospital, Cincinnati, Ohio.
authors.forename: Carolyn M
authors.initials: CM
authors.lastname: Kercsmar
authors.affiliation: University of Texas Southwestern Medical Center, Dallas, Tex.
authors.forename: Rebecca S
authors.initials: RS
authors.lastname: Gruchalla
authors.affiliation: College of Physicians and Surgeons, Columbia University, New York, NY.
authors.forename: Meyer
authors.initials: M
authors.lastname: Kattan
authors.affiliation: Children's National Health System and the George Washington University School of Medicine and Health Sciences, Washington, DC.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Teach
authors.affiliation: Henry Ford Health System, Detroit, Mich.
authors.forename: Christine C
authors.initials: CC
authors.lastname: Johnson
authors.affiliation: St Louis Children's Hospital, St Louis, Mo.
authors.forename: Leonard B
authors.initials: LB
authors.lastname: Bacharier
authors.affiliation: University of Wisconsin School of Medicine and Public Health, Madison, Wis.
authors.forename: James E
authors.initials: JE
authors.lastname: Gern
authors.affiliation: National Institute of Allergy and Infectious Diseases, Bethesda, Md.
authors.forename: Steven M
authors.initials: SM
authors.lastname: Sigelman
authors.affiliation: National Institute of Allergy and Infectious Diseases, Bethesda, Md.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Gergen
authors.affiliation: National Institute of Allergy and Infectious Diseases, Bethesda, Md.
authors.forename: Alkis
authors.initials: A
authors.lastname: Togias
authors.affiliation: Rho Federal Systems Division, Chapel Hill, NC.
authors.forename: Cynthia M
authors.initials: CM
authors.lastname: Visness
authors.affiliation: University of Wisconsin School of Medicine and Public Health, Madison, Wis.
authors.forename: William W
authors.initials: WW
authors.lastname: Busse
authors.affiliation: National Jewish Health, Denver, and Children's Hospital Colorado and University of Colorado School of Medicine, Aurora, Colo.
authors.forename: Andrew H
authors.initials: AH
authors.lastname: Liu
mesh_terms: D000293:Adolescent; D017668:Age of Onset; D018927:Anti-Asthmatic Agents / Q000627:therapeutic use*; D001249:Asthma / Q000150:complications / Q000188:drug therapy* / Q000503:physiopathology*; D015142:Baltimore; D002648:Child; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008487:Medical History Taking; D011203:Poverty; D011446:Prospective Studies; D012220:Rhinitis / Q000150:complications / Q000188:drug therapy / Q000503:physiopathology; D012720:Severity of Illness Index; D014505:Urban Population
chemical_list: D018927:Anti-Asthmatic Agents
keywords: Child; IgE; allergen sensitization; asthma; asthma exacerbations; asthma morbidity; asthma phenotype; asthma severity; inner-city asthma; pulmonary function; rhinitis