Characteristics of anaphylaxis patients who visited emergency departments in Korea: Results from a national emergency department information system.

Background: Anaphylaxis is an allergic disease with fatal respiratory or cardiovascular symptoms that require immediate emergency treatment. We aimed to understand the characteristics and frequency of emergency department (ED) visits of patients with anaphylaxis in Korea.

Methods: Between 2007 and 2013, using data from 147 ED from the National Emergency Department Information System in Korea, we retrospectively evaluated patients with a primary diagnosis of anaphylaxis.

Results: During the study, a total 23,313 patients visited the ED due to anaphylaxis. The number of patients with anaphylaxis who visited the ED increased from 3.0 per 100,000 population in 2007 to 11.6 per 100,000 population in 2013 (P<0.001). Overall, the frequency of anaphylaxis emergency department visits increased by 1.24 times each year (95% CI 1.23-1.25). The risk of visiting ED due to anaphylaxis by population-based age-specific group was highest in the 60-69 years old (OR 2.30, 95% CI 1.96-2.70). Deaths from anaphylaxis increased by 1.35 times per year (95% CI 1.13-1.62). The causes of anaphylaxis were unknown (80.8%; 95% CI 80.35-81.38), drugs (8.9%; 95% CI 8.47-9.24), food (4.1%; 95% CI 3.87-4.39), bees (3.2%; 95% CI 3.02-3.48) and arthropods (2.3%; 95% CI 2.11-2.48). In 2009, drugs were the most common cause of anaphylaxis in November (35.5%), followed by food in May (15.5%) (P<0.001). Between July and September, stings from insects were the most common causes (P<0.001). By age, food was the most common cause in children aged <6 years (7.6%, <12 months; 9.0%, 1-6 years) and drugs in those aged ≥7 years. The 7-year overall mortality rate was 0.104 case per 1,000,000 population; men accounted for 77.8% of the deaths. By region, the number of cases was the highest in metropolitan areas, Gyeonggi and Seoul; however, the number of anaphylaxis cases per 100,000 population was the highest in Jeju and Gangwon.

Conclusion: Based on ICD-10 codes, the number of ED visits due to anaphylaxis is increasing in Korea, and the incidence of anaphylaxis varies by region, season, and age.