Prospective multicenter study of acute asthma in younger versus older adults presenting to the emergency department

OBJECTIVES: To describe acute asthma in younger versus older adults presenting to the emergency department (ED). DESIGN: Prospective cohort study. Asthmatic adults were divided into three age groups: 18 to 34, 35 to 54, and 55 and older. The analysis was restricted to never smokers and smokers with fewer than 10 pack-years. SETTING: ED. PARTICIPANTS: Two thousand sixty-four patients aged 18 and older with a physician diagnosis of asthma. MEASUREMENTS: Medications and peak expiratory flow. RESULTS: There were 1,158 (56%) subjects aged 18 to 34; 777 (37%) aged 35 to 54; and 129 (6%) aged 55 and older. Older patients were most likely to have a primary care provider (65%, 74%, and 91%, respectively; P < .001); most were not taking inhaled corticosteroids (39%, 55%, and 48%, respectively; P <.001). Older patients reported fewer ED visits for asthma (2, 2, and 1, respectively; P=.001) but were more likely to report asthma hospitalization (24%, 31%, and 37%, respectively; P <.001). All groups had severe exacerbations (initial percentage predicted peak flow: 47, 47, and 47, respectively; P=.50), but older patients were least likely to report severe symptoms (72%, 79%, and 67%, respectively; P=.001). Older patients did not respond as well to bronchodilators, even after controlling for other demographic factors, markers of asthma severity, and ED management (change between initial and final peak expiratory flow, using subjects aged 18 to 34 as reference: aged 35-54, beta=-0.7 (95% CI=-9.4-8.0); aged >= 55, beta=-18.4 (-31.9 to -4.9)). The smaller change in peak expiratory flow contributed most to older patients' greater likelihood of hospitalization. CONCLUSION: Older asthma patients were less responsive to emergency bronchodilation. This may reflect chronic undertreatment with inhaled corticosteroids.