Temporal trends in emergency department visits for bronchiolitis in the United States, 2006 to 2010

Abstract

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.

Figure. Rates of US ED Visits for Bronchiolitis per 1000 Children, According to Age Group and Different Definitions; 2006-2010

Between 2006 and 2010, there was a significant increase in the overall rate of bronchiolitis ED visits among children age <2 years (2% increase; P_trend=0.008), and the subgroup of children from 12 months to 23 months (24% increase; P_trend<0.001). By contrast, there was a significant decline in the rate among children age <12 months (4% decrease; P_trend<0.001), and the subgroup of children age <12 month with bronchiolitis as the primary diagnosis and no high-risk medical conditions (6% decrease; P_trend<0.001). I bars represent 95% confidence intervals.