Multicenter study of clinical features of sudden-onset versus slower-onset asthma exacerbations requiring hospitalization.
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.