Rate, associated factors and outcomes of recurrence of Kawasaki disease in Ontario, Canada

Background: Previous studies on recurrence of Kawasaki disease (KD) have mostly been limited to Japan, which has an incidence of KD 810-fold higher than North America. The aim of the present study was to determine the rate of KD recurrence for patients in Ontario, to identify factors potentially associated with increased odds of recurrence, and to compare the clinical course and outcomes of index and recurrent KD episodes. Methods: Review was undertaken of all patients with recurrence of KD identified in Ontario, Canada, from 1995 to 2006. All patients with recurrence of KD (defined as at least three clinical signs of KD in addition to fever =5 days), presenting =14 days after the return to baseline from the index episode were included. Results: A total of 1010 patients were followed for 5786 patient-years. During this period a total of 17 recurrent episodes in 16 patients were identified at a median of 1.5 years after the initial episode (2 weeks5 years). Rate of recurrence of KD was 2.9 episodes/1000 patient-years, which is higher than the expected annual incidence of KD in the same age group (26.2/100 000 per year). No factors associated with increased risk of recurrence were identified, perhaps due to the small number of events. Clinical course and outcomes of the index and recurrent KD episodes were similar. Conclusions: A previous history of KD should increase the index of suspicion for future episodes of KD to allow for rapid recognition, treatment and to achieve optimal outcomes.