Objective: Since 1970, twelve nationwide epidemiologic surveys of Kawasaki disease (KD) have been conducted throughout Japan every two years to describe KD in Japan. By the end of 1992, a total of 116,848 cases were reported. This paper summarizes the statistical analysis of the latest survey for the 2-year period from January 1991 through December 1992.
Method: A questionnaire form and diagnostic guidelines for KD were sent to all pediatric departments of hospitals with 100 or more beds throughout Japan and information was obtained on patients with KD diagnosed during the 2-year period from January 1991 through December 1992.
Results: The summary of the results is: 1) the number of patients reported was 11,221 (6604 males and 4617 females; male/female ratio = 1.43) with a yearly incidence rate of 90 per 100,000 children < 5 years old; 2) the monthly number of patients was higher in winter and summer, although the monthly difference was not marked; 3) age-specific incidence rates showed a unimodal peak at 1 year of age; 4) the proportion of patients with a family history of KD in a sibling was 1%; 5) the proportion of recurrent patients was 3%; 6) the proportion of patients with cardiac sequelae 1 month after disease onset was 13%; and 7) the number of patients who died was 9, which conforms to 0.08% of total patients.
Conclusion: The incidence rates of KD in Japan are ten times higher than those reported in western countries and almost constant over 6 years. The descriptive epidemiology of the disease, which supports the infection theory, does not change for years.