Cumulative incidence of Kawasaki disease with cardiac sequelae in Japan

BACKGROUND: Some patients with Kawasaki disease (KD) develop cardiac sequelae, which increases the risk of subsequent ischemic heart events. Knowing the cumulative incidence (CI) of KD with cardiac sequelae may contribute to developing health promotion policies to prevent subsequent ischemic events in these patients. METHODS: Study subjects consisted of 254,984 patients aged 0 to 9 years with KD who were registered in nationwide surveys in Japan from 1991 through 2016. We calculated the incidence probabilities, dividing the number of patients with KD age 0 to 5-9 years by the population used in vital statistics of each calendar year. We calculated the cumulative proportion of those not affected by KD, by multiplying each probability from age 0 to 5-9 years. The CI of KD was obtained by subtracting this value from 1. We also calculated the number of patients in each birth cohort (CIBC). The same was done to calculate the CI of KD-related cardiac sequelae. RESULTS: The CIBC steadily increased from 0.005067 in males and 0.003668 in females in 1991 to 0.011431 in males and 0.0088253 in females in 2007. The CIBC of KD with cardiac sequelae decreased from 0.000478 in males and 0.000213 in females in 1997 to 0.000339 in males and 0.000169 in females in 2007. CONCLUSION: The increasing CIBC of KD indicates an increased susceptibility to KD in accordance with birth year. The decreasing CIBC of cardiac sequelae suggests the efficacy of the treatment of KD.