Temporal trends in emergency department visits for bronchiolitis in the United States, 2006 to 2010.
BACKGROUND
To examine temporal trends in emergency departments (EDs) visits for bronchiolitis among US children between 2006 and 2010.


METHODS
Serial, cross-sectional analysis of the Nationwide Emergency Department Sample, a nationally representative sample of ED patients. We used International Classification of Diseases, Ninth Revision, Clinical Modification code 466.1 to identify children <2 years of age with bronchiolitis. Primary outcome measures were rate of bronchiolitis ED visits, hospital admission rate and ED charges.


RESULTS
Between 2006 and 2010, weighted national discharge data included 1,435,110 ED visits with bronchiolitis. There was a modest increase in the rate of bronchiolitis ED visits, from 35.6 to 36.3 per 1000 person-years (2% increase; Ptrend = 0.008), due to increases in the ED visit rate among children from 12 months to 23 months (24% increase;Ptrend < 0.001). By contrast, there was a significant decline in the ED visit rate among infants (4% decrease; Ptrend < 0.001). Although unadjusted admission rate did not change between 2006 and 2010 (26% in both years), admission rate declined significantly after adjusting for potential patient- and ED-level confounders (adjusted odds ratio for comparison of 2010 with 2006, 0.84; 95% confidence interval: 0.76-0.93; P < 0.001). Nationwide ED charges for bronchiolitis increased from $337 million to $389 million (16% increase; Ptrend < 0.001), adjusted for inflation. This increase was driven by a rise in geometric mean of ED charges per case from $887 to $1059 (19% increase; Ptrend < 0.001).


CONCLUSIONS
Between 2006 and 2010, we found a divergent temporal trend in the rate of bronchiolitis ED visits by age group. Despite a significant increase in associated ED charges, ED-associated hospital admission rates for bronchiolitis significantly decreased over this same period.
From the *Massachusetts General Hospital; †Harvard Medical School; ‡Beth Israel Deaconess Medical Center, Boston, MA; §Center for Clinical Epidemiology of St. Luke's Life Science Institute, Tokyo, Japan; and ¶Boston Children's Hospital, Boston, MA.
Kohei
K
Hasegawa
Yusuke
Y
Tsugawa
David F M
DF
Brown
Jonathan M
JM
Mansbach
Carlos A
CA
Camargo
D001988:Bronchiolitis / Q000453:epidemiology* / Q000401:mortality; D003430:Cross-Sectional Studies; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D007902:Length of Stay; D008297:Male; D016896:Treatment Outcome; D014481:United States / Q000453:epidemiology