The age-related characteristics of adults with asthma who visited emergency departments in Korea from 2007 to 2012

Background Understanding the patterns of emergency department (ED) visits of patients with asthma is important for disease control and prevention of exacerbations. Objective This study aimed to investigate the characteristics of adult patients who visited EDs because of their asthma. Methods Patients with asthma, ages ≥19 years old, who visited 117 EDs throughout Korea between January 2007 and December 2012 were identified in the National Emergency Department Information System (NEDIS) data base using the International Classification of Disease, 10th revision, codes J45 (asthma) and J46 (status asthmaticus). Results A total of 97,835 adult patients with asthma visited 117 EDs throughout Korea during the study period. There was a slight female preponderance (male-to-female ratio, 1:1.09). The number of patients aged 70-79-years-old was 28,031 (28.7%), the highest among the patients with asthma. ED visits showed a seasonal distribution, with most occurring in winter and spring, followed by autumn. The seasonal distribution varied by age; most patients ages 19-49 years presented in autumn (September), whereas those patients ages ≥50 years presented to the ED most often in winter. Overall, 65.5% of patients were admitted to the hospital, including 12.6% admitted to an intensive care unit (ICU). Overall, 209 patients (0.2%) died. The rates of hospital admission to general wards and ICUs were highest in those patients ≥70 years old; this group also had the highest mortality rate. Conclusion In this nationwide study, which spanned 6 years, of adult patients with asthma, we observed an age-specific seasonal pattern of ED visits. Identifying the causes of age-related deterioration and seasonal visits to the ED will help prevent asthma symptoms and reduce medical costs.