title: A prospective multicenter study of factors associated with hospital admission among adults with acute asthma.
abstract: OBJECTIVE
  We sought to determine patient characteristics associated with hospital admission after emergency treatment for asthma, and whether disposition guidelines are followed.
  
  
  METHODS
  We performed a prospective multicenter cohort study involving 64 emergency departments in the United States and Canada. Consecutive adult patients with asthma exacerbations were interviewed, and their charts were reviewed using standardized protocols. Telephone follow-up at 2 weeks determined relapse.
  
  
  RESULTS
  Of 1805 patients, 363 (20%; 95% confidence interval [CI]: 18% to 22%) were hospitalized. Among patients with severe exacerbations (final peak flow <50% of predicted), 122 (49%; 95% CI: 43% to 55%) were hospitalized. Admission was associated with final peak flow, female sex, nonwhite race, severity of chronic illness, and severity of exacerbation. Admission predictors were similar regardless of hospital funding, region, or size. Among patients with mild or moderate exacerbations of asthma (peak flow >or=50% predicted), the likelihood of admission was associated significantly with the number of predefined risk factors for death from asthma. Of patients who were discharged from the emergency department, 62 (5%; 95% CI: 4% to 6%) relapsed within 72 hours. Relapse was not associated with final peak flow (P = 0.39).
  
  
  CONCLUSIONS
  Associations between patient characteristics and disposition were similar across sites. Despite guidelines to the contrary, half of patients with final peak flow <50% were discharged. After emergency department treatment and discharge, short-term relapse was uncommon among patients with asthma, suggesting that strict peak flow cutoffs may be unnecessary if risk factors in patients with mild or moderate exacerbations are considered.
authors.affiliation: Division of Emergency Medicine, University of California, San Francisco, San Francisco, California 94143, USA. weber@medicine.ucsf.edu
authors.forename: Ellen J
authors.initials: EJ
authors.lastname: Weber
authors.forename: Robert A
authors.initials: RA
authors.lastname: Silverman
authors.forename: Michael L
authors.initials: ML
authors.lastname: Callaham
authors.forename: Charles V
authors.initials: CV
authors.lastname: Pollack
authors.forename: Prescott G
authors.initials: PG
authors.lastname: Woodruff
authors.forename: Sunday
authors.initials: S
authors.lastname: Clark
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Camargo
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D001249:Asthma / Q000628:therapy*; D015331:Cohort Studies; D004632:Emergency Medical Services / Q000592:standards* / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010343:Patient Admission / Q000592:standards* / Q000706:statistics & numerical data*; D018579:Patient Selection; D017410:Practice Guidelines as Topic / Q000592:standards*; D011446:Prospective Studies; D012129:Respiratory Function Tests; D012720:Severity of Illness Index