Follow up of Kawasaki disease based on nationwide survey data in Japan: Mortality among those with a history of Kawasaki disease in Japan: Results of a 30‐year follow up

BackgroundThe long‐term prognosis of those with a history of Kawasaki disease (KD) is still unknown.MethodsUsing a permanent registry system in Japan (koseki), 6,576 persons with a history of KD were followed up. The average follow‐up period was 30 years. The endpoint was death.ResultsWith a 99.5% follow‐up rate, 68 deaths (48 males and 20 females) were observed. The overall standardized mortality ratio, of which reference was vital statistics in Japan, was not elevated. However, the observation according to the presence or absence of cardiac sequelae showed that the standardized mortality ratio for those with cardiac sequelae significantly elevated. Nine persons, all of whom were males, died of KD (including those cases where KD was suspected), but all deaths occurred in individuals who were under 30 years of age.ConclusionsThis study revealed the long‐term prognosis for KD, but almost all participants were younger than 40 years. Continuing follow up of this cohort is required to clarify whether a history of KD relates to the development of atherosclerosis when participants become middle aged or older.