title: Assessment of severity measures for acute asthma outcomes: a first step in developing an asthma clinical prediction rule.
abstract: OBJECTIVE
  As a first step in the development of an asthma prediction rule, our primary objective was to assess the association of 8 candidate predictor variables with 2 clinically relevant asthma outcomes.
  
  
  METHODS
  Among a cohort of 125 adults hospitalized with an asthma exacerbation, we examined models to identify clinical variables associated with length of stay (LOS) and clinically significant asthma exacerbations within 3 months after hospitalization (3-month exacerbation). Eight candidate predictor variables were chosen, including age, sex, race, pulsus paradoxus, prior endotracheal intubation for asthma, hospitalization within 5 years for asthma, and 2 chronic asthma severity scores.
  
  
  RESULTS
  We found independent associations between LOS and pulsus paradoxus (P = .005), prior intubation (P = .03), sex (P = .03), and prior hospitalization (P = .019). Among men, 52% had a 3-month exacerbation in comparison with 25% of women; and in multivariable analysis, male sex was independently associated with 3-month exacerbation (adjusted odds ratio = 5.1; 95% confidence interval = 1.37-18.9; P = .015). Participants with 3-month exacerbation had higher Johns Hopkins Allergy and Asthma Composite (JHAAC) chronic severity scores (median = 77; interquartile range = 57-91) than those who did not (median = 54; interquartile range = 35-69; P < .001) (for 40-unit increase, adjusted OR for 3-month exacerbation = 1.54; 95% confidence interval = 1.16-2.03; P = .003). In multivariable analysis, male sex and the JHAAC severity score were independently associated with 3-month exacerbation.
  
  
  CONCLUSIONS
  Elevated pulsus paradoxus, prior intubation for asthma, and 5-year asthma hospitalization are independently associated with LOS. Race, 5-year asthma hospitalization, and JHAAC score predict 3-month asthma exacerbation. These variables warrant consideration for use in the development of an asthma prediction rule.
authors.affiliation: Department of Emergency Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232-4700, USA. don.arnold@vanderbilt.edu
authors.forename: Donald H
authors.initials: DH
authors.lastname: Arnold
authors.forename: Tebeb
authors.initials: T
authors.lastname: Gebretsadik
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Minton
authors.forename: Stanley
authors.initials: S
authors.lastname: Higgins
authors.forename: Tina V
authors.initials: TV
authors.lastname: Hartert
mesh_terms: D000208:Acute Disease; D000328:Adult; D001249:Asthma / Q000175:diagnosis*; D004636:Emergency Service, Hospital; D005260:Female; D006801:Humans; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D017063:Outcome Assessment, Health Care; D010343:Patient Admission; D011379:Prognosis; D012720:Severity of Illness Index