title: Asthma severity, not asthma control, is worse in atopic compared with nonatopic adolescents with asthma.
abstract: BACKGROUND
  The effects of atopic and nonatopic asthma phenotypes on asthma morbidity are unclear. Moreover, asthma morbidity in patients without atopy might be mediated by immunoglobulin E (IgE).
  
  
  OBJECTIVE
  To determine differences in morbidity in patients with asthma with and without atopy in a population of inner-city adolescents with asthma and to assess the impact of total IgE (tIgE) in this population.
  
  
  METHODS
  Data were obtained from 546 inner-city adolescents in the Asthma Control Evaluation study. A positive skin prick test reaction to 14 aeroallergens and specific IgE to 5 aeroallergens determined atopic status. High (≥75th percentile) and low (≤25th percentile) tIgE levels were categorized. Asthma control (Asthma Control Test) and asthma severity (Composite Asthma Severity Index [CASI]) were measured at multiple time points over 1 year. Fractional exhaled nitric oxide (FeNO) and measurements of morbidity also were collected. Multivariable and repeated measures analyses modeled the relation between atopic status and morbidity.
  
  
  RESULTS
  Baseline CASI scores increased 0.90 point (P < .05) and FeNO increased 0.85 natural logarithmic unit (P < .001) in participants with vs without atopy. Repeated measures analyses showed consistent results. Participants without atopy and increased tIgE had FeNO 0.73 natural log unit higher (P < .01) than low tIgE and a nonsignificant increase in CASI. The CASI score and FeNO levels were higher for high than for low tIgE in participants with atopy.
  
  
  CONCLUSIONS
  In this population, participants with atopic asthma had worse asthma severity and higher FeNO compared with those with nonatopic asthma, but no difference in control. In all participants, higher tIgE indicated worse severity and higher FeNO. In this population, asthma severity and FeNO might be mediated by IgE in the 2 asthma phenotypes.
authors.affiliation: Tulane University School of Public Health, New Orleans, Louisiana; Social & Scientific Systems, Inc, Silver Spring, Maryland. Electronic address: warroyav@s-3.com.
authors.forename: Whitney D
authors.initials: WD
authors.lastname: Arroyave
authors.affiliation: Tulane University School of Public Health, New Orleans, Louisiana.
authors.forename: Felicia A
authors.initials: FA
authors.lastname: Rabito
authors.affiliation: Tulane University School of Medicine, New Orleans, Louisiana.
authors.forename: John C
authors.initials: JC
authors.lastname: Carlson
authors.affiliation: Rho, Chapel Hill, North Carolina.
authors.forename: Michelle L
authors.initials: ML
authors.lastname: Sever
authors.affiliation: Tulane University School of Public Health, New Orleans, Louisiana.
authors.forename: John
authors.initials: J
authors.lastname: Lefante
mesh_terms: D000293:Adolescent; D000485:Allergens / Q000276:immunology; D001249:Asthma / Q000188:drug therapy / Q000276:immunology* / Q000378:metabolism / Q000503:physiopathology; D002648:Child; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000276:immunology* / Q000378:metabolism / Q000503:physiopathology; D007073:Immunoglobulin E / Q000097:blood / Q000276:immunology*; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism; D010641:Phenotype; D012882:Skin Tests
chemical_list: D000485:Allergens; D009569:Nitric Oxide; D007073:Immunoglobulin E