Epidemiologic features of Kawasaki disease in South Korea: data from nationwide survey, 2009-2011

To assess the recent epidemiologic features of Kawasaki disease (KD) in South Korea from the nationwide survey conducted between 2009 and 2011.We collected data regarding the incidence, symptoms, treatment and coronary complications associated with acute KD by sending questionnaires to the 100 hospitals that have pediatric residency programs from 2009 to 2011.We received complete responses from 73 hospitals and partial responses from 14 hospitals. A total of 13,031 patients of KD were reported from the 87 hospitals (3941 in 2009, 4635 in 2010 and 4455 in 2011). The male to female ratio was 1.44:1, and the median age at diagnosis was 28 months. From the questionnaires with complete responses, we noted that the incidence of KD per 100,000 children5 years of age was 115.4 in 2009, 132.9 in 2010 and 134.4 in 2011 (average rate, 127.7). KD occurred more frequently during summer (June, July and August) and during winter (December and January). The recurrence rate was 3.83%. The standard dose of intravenous immunoglobulin was administered to 93.6% of the patients, and nonresponder rate was 11.6%. Coronary aneurysm occurred in 1.9% of the patients and giant aneurysm developed in 26 patients (0.26%) over 3 years, and 2 patients had myocardial infarction. No mortality was reported.The average annual incidence of KD in South Korea has continuously increased to 134.4 per 100,000 children5 years of age in 2011, which is the second highest incidence of KD worldwide, following its incidence in Japan.