Childhood asthma hospitalizations in the United States, 2000-2009

Abstract

Objective: To examine temporal trends in the US incidence of childhood asthma hospitalizations, in-hospital mortality, mechanical ventilation use, and hospital charges between 2000 and 2009.

Study design: This was a serial, cross-sectional analysis of a nationally representative sample of children hospitalized with acute asthma. The Kids Inpatient Database was used to identify children aged <18 years with asthma by International Classification of Diseases, Ninth Revision, Clinical Modification code 493.xx. Outcome measures were asthma hospitalization incidence, in-hospital mortality, mechanical ventilation use, and hospital charges. We examined temporal trends of each outcome, accounting for sampling weights. Hospital charges were adjusted for inflation to 2009 US dollars.

Results: The 4 separate years (2000, 2003, 2006, and 2009) of national discharge data included a total of 592805 weighted discharges with asthma. Between 2000 and 2009, the rate of asthma hospitalization in US children decreased from 21.1 to 18.4 per 10000 person-years (13% decrease; Ptrend < .001). Mortality declined significantly after adjusting for confounders (OR for comparison of 2009 with 2000, 0.37; 95% CI, 0.17-0.79). In contrast, there was an increase in the use of mechanical ventilation (from 0.8% to 1.0%, a 28% increase; Ptrend < .001). Nationwide hospital charges also increased from $1.27 billion to $1.59 billion (26% increase; Ptrend < .001); this increase was driven by a rise in the geometric mean of hospital charges per discharge, from $5940 to $8410 (42% increase; Ptrend < .001).

Conclusion: Between 2000 and 2009, we found significant declines in asthma hospitalization and in-hospital mortality among US children. In contrast, mechanical ventilation use and hospital charges for asthma increased significantly over this same period.

Keywords: AHRQ; Agency for Healthcare Research and Quality; CCS; Clinical Classifications Software; HCUP; Healthcare Cost and Utilization Project; ICD-9-CM; International Classification of Diseases, Ninth Revision, Clinical Modification; KID; Kids' Inpatient Database.

Figure 1

Incidence Rates of US Asthma Hospitalizations per 10 000 Children, According to Age Group, 2000-2009. Between 2000 and 2009, there was a significant decline in the incidence rate of asthma hospitalization among overall US children (13% decrease; P_trend<.001), the 0- to 4-year-old age group (21% decrease; P_trend<.001), and the 12- to 17-year-old age group (25% decrease; P_trend<.001). The incidence rate among the 5- to 11-year-old age group did not change significantly (P_trend=.31).

Figure 2

In-hospital Health Care Utilization and Hospital Charges for Childhood Asthma Hospitalizations, 2000-2009. Between 2000 and 2009, use of mechanical ventilation increased (28% increase; P_trend<.001); use of non-invasive mechanical ventilation also increased (292% increase; P_trend<.001). The geometric mean of hospital charges per case increased significantly (42% increase; P_trend<.001), adjusted for inflation.

Figure 3

Incidence Rates of Asthma, Pneumonia, Bronchiolitis, Bronchitis, and Wheezing Hospitalizations per 10 000 Children; 2000-2009. For all disease groups, a decreasing trend in incidence of hospitalization was seen across all study years (P_trend<.001).