Epidemiology of Chronic Urticaria in Korea Using the Korean Health Insurance Database, 2010-2014

Purpose: There are very few epidemiological studies on chronic urticaria (CU). We aimed to investigate the prevalence of CU and to depict demo-graphics and medication patterns for the disease in a nationwide population-based study. Methods: Data on urticaria (L50 of the International Classification of Diseases, 10th revision) from 2010 to 2014 were obtained from the Korean Health Insurance Review and Assessment Service. Algorithms designed to evaluate prescription drug claims for antihistamines were applied to identify CU. Results: The crude prevalence of CU was 2,256.5 per 100,000 person-years and tended to increase every year. The age-standardized prevalence of CU was significantly higher in females than in males (2,466.8 vs 1,819.2 per 100,000 person-years, P<0.001). Age-specific prevalence was highest for older adults over the age of 65 years and lowest for ages 10-29 years. The median duration of CU was 591 days, and symptoms lasted for at least 1 year in 61.9% of patients. Gastrointestinal disease was the most common comorbidity in adults, whereas allergic rhinitis and common cold were more prevalent in children with CU. Around a third of CU patients were taking antihistamine treatment alone, and 70% were treated with both antihistamines and systemic corticosteroids. Cyclosporine was prescribed for 0.02% of CU patients. Conclusions: The present study outlines recent longitudinal epidemiological data on the prevalence of CU in Korea. In light of limitations on the use of claims data, including no specific disease code for CU and a possible discordance between drug claims and the presence of urticaria symptoms, further investigations are necessary to describe the exact epidemiologic profile of CU patients.