Epidemiologic features of Kawasaki disease in Japan: results from the nationwide survey in 2005-2006.

BACKGROUND: The most recent epidemiologic features of Kawasaki disease are unknown. METHODS: The 19th nationwide survey of the disease was conducted in 2007, targeting patients who were affected by this disease in 2005 and 2006. All pediatric departments in hospitals with 100 or more beds and pediatric hospitals were asked to report all Kawasaki disease patients during the 2 survey years. RESULTS: From 1543 departments and hospitals, a total of 20475 patients (10041 in 2005 and 10434 in 2006) were reported. There were 11892 male patients and 8583 female patients. The average annual incidence rate was 184.6 per 100000 children aged 0-4 years. The number of patients and the incidence rate have increased significantly during the past 12 years. The age-specific incidence rate was distributed monomodally with a peak at 6-8 months of age. The prevalence of cardiac lesions in the acute phase of the disease and of cardiac sequelae were higher among infants and old patients. CONCLUSION: The number of patients with Kawasaki disease and its incidence rate in Japan are continuously increasing.