Age-related differences in clinical outcomes for acute asthma in the United States, 2006-2008

Little is known about the effect of age on acute asthma outcomes.

We sought to investigate age-related differences in the emergency department (ED) presentation and clinical outcomes for patients with acute asthma.

We analyzed the 2006-2008 Nationwide Emergency Department Sample, the largest, all-payer, US ED and inpatient database. ED visits for acute asthma were identified with a principal diagnosis of International Classification of Disease, ninth revision, Clinical Modification code 493.xx. Patients were divided into 3 age groups: children (<18 years), younger adults (18-54 years), and older adults (≥55 years). The outcome measures were in-hospital all-cause mortality, near-fatal asthma-related events (noninvasive or mechanical ventilation), hospital charges, admission rates, and hospital length of stay.

There were an estimated 1,813,000 visits annually for acute asthma from approximately 4,700 EDs. The estimated overall annual number of in-hospital asthma-related deaths was 1,144 (0.06%); 101 died in the ED, and 1,043 died as inpatients. By age group, there were 37 asthma-related deaths per year in children, 204 in younger adults, and 903 in older adults. Compared with younger adults, older adults had higher mortality, had higher rates of near-fatal asthma-related events, had higher hospital charges, were more likely to be hospitalized, and had a longer hospital length of stay (P < .001 for all). After adjusting for comorbidities, older asthmatic patients had a 5-fold increased risk of overall mortality (adjusted odds ratio, 5.2; 95% CI, 4.0-6.9), compared with younger adults.

Older adults with acute asthma have a substantial burden of morbidity and mortality. With the US population aging, there is an urgent need for targeted interventions for this high-risk population.