A population-based epidemiological study of anaphylaxis using national big data in Korea: trends in age-specific prevalence and epinephrine use in 2010-2014

Background: Previous reports on anaphylaxis in Asia are limited to relatively small-scale studies. We performed this study to identify the nationwide prevalence of anaphylaxis and epinephrine prescription rates by age groups. Methods: The total number of patients, yearly and overall prevalence, percentage of emergency department visits, and epinephrine prescription rates were calculated for patients diagnosed with anaphylaxis based on the Korean National Health Insurance database from 2010 to 2014. Results: The mean prevalence of anaphylaxis in Korea was 26.23 (95% confidence interval, CI 25.78-26.68) per 100,000 person-years during the 5 years. It increased from 20.55 (95% CI 20.15-20.10) in 2010 to 35.33 (95% CI 34.81-35.85) per 100,000 person-years in 2014. The average prevalence was > 35 per 100,000 person-years among 50-69 year-olds, and the mean crude prevalence in children was 22.3 (0-2 years), 17.3 (3-6 years), 12.1 (7-12 years), and 14.9 (13-17 years) per 100,000 person-years, respectively. The overall prevalence increased 1.7-fold, with the highest rate of increase in 0-2 years of age. The overall percentage of emergent anaphylaxis patients was 88.4%, and the prevalence of emergent anaphylaxis increased from 18.63 (95% CI 18.25-19.01) to 31.28 (95% CI 30.79-31.77) per 100,000 person-years. In-hospital epinephrine prescription rate increased from 31.5 to 39.7%. Conclusions: The mean prevalence of anaphylaxis in Korea was 26.2 per 100,000 person-years during the study period. The total number of anaphylaxis patients increased 1.7-fold from 2010 to 2014, with the most noticeable increment being in young children.