Relationship between the cumulative incidence of Kawasaki disease and the prevalence of electrocardiographic abnormalities in birth-year cohorts

Cumulative incidence of Kawasaki disease with cardiac sequelae in Japan

BACKGROUND

Some patients with Kawasaki disease (KD) develop cardiac sequelae, which increase the risk of subsequent ischemic heart events. Knowing the cumulative incidence (CI) of KD with cardiac sequelae may contribute to developing health policies to prevent subsequent ischemic events in these patients.

METHODS

Study participants consisted of 254 984 patients aged 0-9 years with KD who were registered in nationwide surveys in Japan from 1991-2016. We calculated the incidence probabilities by dividing the number of patients with KD aged 0-9 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 in patients aged from age 0-9 years. The CI of KD was obtained by subtracting this value from 1. We also calculated the number of patients in each birth cohort (BC). 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 KD treatment.

Cumulative incidence of Kawasaki disease in Japan

BACKGROUND

Although the incidence rates of Kawasaki disease (KD) in Japan have been determined in nationwide surveys, the cumulative incidence, that is, the proportion of those with a history of KD in the general population of 10-year-olds, is currently unknown. The aim of this study was therefore to assess the cumulative incidence of KD in Japan.

METHODS

Using the age- and sex-specific incidence rate of KD in Japan from the results of the nationwide surveys, incidence probabilities, that is, the age-specific number of KD patients divided by the population used in the vital statistics, and cumulative proportions of those not affected by KD up to the end of 9 years of age, were calculated. The cumulative incidence was then defined as 1 minus the cumulative proportion. The observed age classes were 0, 1, 2, 3, 4, and 5-9 years. All data were calculated by sex.

RESULTS

The cumulative incidence was 0.004833 for boys and 0.003474 for girls in 1991, but was 0.015284 and 0.012145 in 2014, respectively. According to these figures, 15.284 per 1,000 boys and 12.145 per 1,000 girls have been affected by KD by the age of 10 years. The birth-cohort cumulative incidences had similar trends.

CONCLUSIONS

More than 10 persons in 1,000 have a history of KD at age 10 years in Japan.

Kawasaki disease: epidemiology and the lessons from it

A half of century has passed since Dr. Tomisaku Kawasaki reported his 50 cases with Kawasaki disease (KD) in 1967. Since then, more than 300 000 cases have been reported to the nationwide epidemiologic surveys in Japan. However, the etiology and risk factors of the disease are still unknown. In this paper, the author emphasizes that the epidemiology of KD may indicate an infectious agent to be a potential trigger of disease in susceptible children.