Clinical characteristics of patients with recurrent Kawasaki disease: a nationwide cohort study of 19 456 patients with minimum 3-year follow up

Objective To identify the clinical characteristics of patients with recurrent Kawasaki disease (KD). Design A nationwide, population-based, cohort study using the Korean National Health Insurance claims database between 2013 and 2016. Patients A total of 19 456 patients under the age of 5 years who were diagnosed with initial episode of KD were included. A minimum follow-up period of 3 years was mandatory for inclusion. Main outcome measures The epidemiological and clinical profiles were compared between KD patients with and without recurrence. Results The overall recurrence rate of KD was 3.84% (n=748), and the median interval to recurrence was 498 days (IQR: 257–860 days). Approximately 70% of all recurrences occurred within 2 years of the initial diagnosis. The annual proportions of recurrence were 40%, 28%, 18%, 8% and 4% from the first to the fifth year following the initial episode, respectively. Recurrence rates were significantly higher in patients aged <1 year than in those aged 4–5 years (4.65% vs 2.22%) and those who showed resistance to an initial dose of intravenous immunoglobulin (IVIG) (10.00% vs 3.18%). Allergic comorbidities and coronary artery complications at the initial episode were not associated with increased rates of recurrence. Conclusions We clearly identified the annual recurrence rates and their intervals from the initial episode according to the various factors identified, including young age and resistance to initial IVIG. Our results, based on a nationwide cohort, can be used as reference for follow-up management in patients with KD and in future studies.