Background: Kawasaki disease (KD) has been diagnosed in more than 60 countries. Seasonal trend of the patients with KD is observed in many countries. Little is known about the difference between the patient groups in the term of high incidence.
Objective: The aim of this study was to characterize the two patient groups during the winter and summer seasons in Japan.
Methods: Epidemiologic characteristics were compared between January and July, through the 22th nationwide survey included patients who visited hospitals during 2011-2012. The proportions of survey items were observed by age-adjustment.
Results: The total number of patients during 2011-12 was 26,691, the number of patients was 2812 in January and 2302 in July, and the male/female ratio was 1.4, respectively. The patients <3 years account for 66% of each group (1854/2812, 1530/2302). The proportion of <8 months of age was 13.0% (365/2812) in January, 17.8% (409/2302) in July, that of 15 months to 3 years was 38.8% (1092/2812), and 33.5% (771/2302). Concurrence with the diagnostic guidelines was examined, the typical cases in July were 1.6% lower than in January, and the suspected cases were 1.3% higher than in January. The suspected cases of less than 4 principle symptoms had 5.3% higher than in January. The treatment cases with γ-globulin started within 5 days of illness were 2.2% less than in July. The cases of cardiac sequelae (giant aneurysm, aneurysm, dilatation, and stenosis) were 0.3% higher than in July. The cases of serum albumin concentration less than 3.2g/dL were 3.6% higher than in July. The percentage of occurrence cardiac sequelae in this class was 9.5% higher than in July.
Discussion: The difference in age distribution in the two patient groups diagnosed in January and July was observed. The symptom had a slight difference, too. These result do not contradict a hypothesis that onset of KD is concerned with plural infections with different seasonal trend and targeting for the specific age. The association between low levels of serum albumin and cardiac sequelae has been known. The association between this class and the patients in the specific season will be clear in future epidemiologic study.
Conclusion: This study clarified part of the characteristic of the patient diagnosed in the different seasons.