title: Multicenter study of clinical features of sudden-onset versus slower-onset asthma exacerbations requiring hospitalization.
abstract: BACKGROUND
  Asthma exacerbations differ in their speed of symptom onset.
  
  
  OBJECTIVE
  To characterize and compare demographic factors, clinical risk factors, and clinical outcomes among hospitalized patients who presented with sudden-onset (<or= 3 h) versus slower-onset asthma exacerbations, across a wide age range.
  
  
  METHODS
  We reviewed the medical records of a random sample of 1,294 patients, ages 2-54 years, admitted in 30 United States hospitals, for acute asthma from January 1999 to May 2000.
  
  
  RESULTS
  Data on duration of symptoms were available for 1,260 (97%) of the patients. Seventy-two patients (6%) had sudden-onset exacerbations. Sudden-onset patients were older than slower-onset patients (30 y vs 19 y, p = 0.03) but did not differ by other sociodemographic characteristics. Markers of chronic asthma severity were similar between the groups. The sudden-onset patients were more likely to present to the emergency department between midnight and 8:00 am, to require intubation, and to be admitted to the intensive care unit (all p < 0.01). The higher risk of intensive care unit admission remained significant even after adjustment for 6 potential confounders (odds ratio 2.5, 95% confidence interval 1.3-4.9). However, hospital stay was shorter in the sudden-onset patients (2.0 d vs 2.7 d, p = 0.01). There was no difference in peak expiratory flow at hospital discharge.
  
  
  CONCLUSIONS
  The sudden-onset patients were older and they more commonly presented to the emergency department between midnight and 8:00 am with severe exacerbations that required intubation and intensive care unit admission. However, the sudden-onset group was discharged from the hospital earlier.
authors.affiliation: Pulmonary and Critical Care Unit, Massachusetts General Hospital, 326 Cambridge Street, Suite 410, Boston, MA 02114, USA.
authors.forename: Venktesh R
authors.initials: VR
authors.lastname: Ramnath
authors.forename: Sunday
authors.initials: S
authors.lastname: Clark
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Camargo
mesh_terms: D000293:Adolescent; D000328:Adult; D018927:Anti-Asthmatic Agents / Q000627:therapeutic use; D001249:Asthma / Q000188:drug therapy / Q000209:etiology / Q000503:physiopathology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006760:Hospitalization; D006801:Humans; D007902:Length of Stay; D008297:Male; D008485:Medical Audit; D008875:Middle Aged; D014481:United States
chemical_list: D018927:Anti-Asthmatic Agents