title: Repeated dyspnea score and percent FEV1 are modest predictors of hospitalization/relapse in patients with acute asthma exacerbation.
abstract: OBJECTIVE
  (1) Compare ideal cut-off points for DS and %FEV1 at 1 and 3 h to predict hospitalization/relapse in subjects with moderate to severe asthma exacerbation (2) Develop a multivariate regression model using DS, %FEV1, demographic, and clinical variables to predict hospitalization/relapse.
  
  
  METHODS
  Subjects with acute exacerbation of asthma (FEV1 <50% predicted following 30 min of standardized treatment: 5 mg nebulized albuterol; 0.5-1.5 mg nebulized ipratropium; and 50 mg oral prednisone) were eligible. All subjects had %FEV1 and DS obtained at baseline and hourly for 3 h. Using hospitalization/relapse as the outcome of interest; we compared the area under the receiveroperator curves (AUC) between the 1 and 3 h DS and %FEV1 measurements, and the AUC for the change in DS and %FEV1 between baseline and hour-3. We determined ideal cut-points for %FEV1 and DS to maximize sensitivity and specificity. Sensitivity, specificity, positive and negative predictive values, and positive and negative likelihood ratios (LR) were compared between %FEV1 and DS. We developed a multivariate regression model examining the association of specific demographic and clinical variables to hospitalization/relapse.
  
  
  RESULTS
  142 patients were included for analysis. The AUC was greatest for the 3-h DS (0.721), followed by the 3-h %FEV1 (0.669). Optimum cut-off values were a DS of 2, and an FEV1 of 42%. These were associated with a +LR for the composite outcome of 3.06 and 2.48 respectively. Logistic regression showed baseline DS, 3-h DS, change in DS, and oxygen use at hour 3 were all associated with the composite outcome.
  
  
  CONCLUSIONS
  The 3-h score for %FEV1 and DS performed better than scores at any other time point and better than either parameter over time. The 3-h DS had the greatest association with the composite outcome. Neither test was a strong enough predictor to be used solely for this purpose.
authors.affiliation: University of Missouri School of Medicine, Columbia, MO, USA.
authors.forename: John E
authors.initials: JE
authors.lastname: Schneider
authors.affiliation: Emergency Medicine Division, Washington University in St. Louis, USA. Electronic address: Lewisl@wusm.wustl.edu.
authors.forename: Lawrence M
authors.initials: LM
authors.lastname: Lewis
authors.affiliation: Emergency Medicine Division, Washington University in St. Louis, USA.
authors.forename: Ian
authors.initials: I
authors.lastname: Ferguson
authors.affiliation: Emergency Medicine Division, Washington University in St. Louis, USA.
authors.forename: Stacey L
authors.initials: SL
authors.lastname: House
authors.affiliation: Division of Biostatistics, Washington University in St. Louis, USA.
authors.forename: Jingxia
authors.initials: J
authors.lastname: Liu
authors.affiliation: MediciNova Inc., La Jolla, CA, USA.
authors.forename: Kazuko
authors.initials: K
authors.lastname: Matsuda
authors.affiliation: MediciNova Inc., La Jolla, CA, USA.
authors.forename: Kirk
authors.initials: K
authors.lastname: Johnson
mesh_terms: D000208:Acute Disease; D058666:Adrenergic beta-2 Receptor Agonists / Q000627:therapeutic use; D000328:Adult; D000420:Albuterol / Q000627:therapeutic use; D001249:Asthma / Q000150:complications / Q000175:diagnosis* / Q000188:drug therapy / Q000503:physiopathology; D001993:Bronchodilator Agents / Q000627:therapeutic use; D004311:Double-Blind Method; D004417:Dyspnea / Q000209:etiology*; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology*; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D007362:Intensive Care Units / Q000706:statistics & numerical data; D009241:Ipratropium / Q000627:therapeutic use; D007902:Length of Stay / Q000706:statistics & numerical data; D008297:Male; D011237:Predictive Value of Tests; D011241:Prednisone / Q000627:therapeutic use; D011379:Prognosis; D012008:Recurrence; D012720:Severity of Illness Index; D014481:United States
chemical_list: D058666:Adrenergic beta-2 Receptor Agonists; D001993:Bronchodilator Agents; D009241:Ipratropium; D000420:Albuterol; D011241:Prednisone
keywords: Asthma exacerbation; Dyspnea score; FEV(1); Hospital admission