The worldwide epidemiology of Kawasaki disease

Spatiotemporal clusters of Kawasaki disease in South Korea from 2008 to 2017: A municipal-level ecological study

INTRODUCTION

As the etiology of Kawasaki disease (KD) remains unknown, identifying spatiotemporal clusters with proper stratification of KD could provide further evidence for investigating the triggers of KD. However, spatiotemporal distributions of KD with sex stratification have never been reported. Therefore, we aimed to analyze the spatiotemporal patterns of KD by sex in South Korea.

METHODS

We extracted epidemiologic week (Epiweek)-based KD cases in patients <5 years of age (ICD-10-CM code: M303) from 2008 to 2017 national health insurance service data at the 250 municipal level. To determine whether spatial autocorrelation and persistent municipal-level clusters exist, year- and sex-stratified global Moran's I statistics, Getis-Ord Gi* statistics, and emerging hotspot analysis on KD incidence were conducted.

RESULTS

A total of 72,510 KD cases were reported between 2008 and 2017 (male-to-female ratio = 1.40:1). Incidence has increased since 2008, with the highest incidence in 2016 (396.8 per 100,000 population). KD had seasonality of winter and summer but different by sex. Positive spatial autocorrelation was consistently reported in every stratum, with the 2011-2014 period having the strongest index value (total sex I = 0.286, p < 0.001; male I = 0.242, p < 0.001; female I = 0.213, p < 0.001). Hot spots were consistently detected in the northern parts, and cold spots were in the southern part for 9 years in both sexes. The emerging hot spot analysis showed new, consecutive, and sporadic hot spots on the northwestern and eastern coasts and new and sporadic cold spots in the southwestern part. However, the distribution and proportion of hot or cold spot types differed according to sex.

DISCUSSION

The spatiotemporal features of KD had limits to concluding that only infectious triggers result in KD occurrence. Therefore, our findings support the notion that KD is a syndrome with multiple factors, including infectious, genetic, and environmental factors, that are associated with sex differences.

Kawasaki Disease and Pediatric Infectious Diseases During the Coronavirus Disease 2019 Pandemic

OBJECTIVE

To assess the epidemiologic association between Kawasaki disease and common pediatric infectious diseases (PIDs) identified during the coronavirus disease 2019 (COVID-19) pandemic period to confirm whether the infection-triggered theory is a plausible hypothesis for the pathogenesis of Kawasaki disease.

STUDY DESIGN

A retrospective epidemiologic study was conducted using datasets obtained from Web-based surveillance of Kawasaki disease and PIDs in Japan. We compared weekly numbers of patients who developed Kawasaki disease and specific PIDs between 2020 and 2017-2019 and evaluated the association between the percent reduction in the number of patients with these diseases.

RESULTS

A total of 868 patients developed Kawasaki disease in 2020. During the social distancing period in 2020, the number of patients with Kawasaki disease was approximately 35% lower than in 2017-2019. Time from the onset of Kawasaki disease until the first hospital visit did not differ significantly among the examined years. The proportion of older children with Kawasaki disease decreased more than that of infants with Kawasaki disease (age <1 year), resulting in a significant difference in the proportion of infant patients between 2020 and 2017-2019 (24% vs 19%; P < .01). The number of patients with incomplete Kawasaki disease was unchanged from that of previous years. The weekly percent reduction in patient numbers differed between Kawasaki disease and PIDs during 2020, with no strong correlation between the 2 diseases.

CONCLUSIONS

Our data indicate that parents of patients with Kawasaki disease did not avoid hospital visits during the COVID-19 pandemic period. The findings indicate the possibility that triggering Kawasaki disease might be associated with presently unidentified respiratory pathogen(s) that potentially might be acquired from both within and outside the household.

Epidemiology, Treatments, and Cardiac Complications in Patients with Kawasaki Disease: The Nationwide Survey in Japan, 2017-2018

OBJECTIVE

To report the epidemiologic characteristics, treatments, and cardiac complications of Kawasaki disease, using data from the nationwide survey in Japan.

STUDY DESIGN

The nationwide Kawasaki disease survey in Japan has been conducted biennially since 1970. The most recent survey was completed in 2019, obtaining information for patients who developed Kawasaki disease during 2017-2018. Survey respondents were hospitals specializing in pediatrics and those with ≥100 beds and a pediatric department throughout Japan, where patients with Kawasaki disease were eventually hospitalized.

RESULTS

The survey identified 32 528 patients with Kawasaki disease, which consisted of 15 164 (46.6%) in 2017 and 17 364 (53.4%) in 2018. The highest annual incidence rate was recorded in 2018 (359 per 100 000 children aged 0-4 years). After 1982, patients with ≤4 principal Kawasaki disease signs gradually increased, resulting in 6847 (21.1%) patients diagnosed during 2017-2018. Among the 30 784 patients receiving initial intravenous immunoglobulin administration, 6061 (19.7%) did not respond. Within 30 days of Kawasaki disease onset, 9.0% of patients were diagnosed with cardiac complications, and 2.6% of patients developed cardiac sequelae after the acute illness.

CONCLUSIONS

The annual number of patients developing Kawasaki disease in Japan increased from 1970 through 2018, whereas the proportion of patients with Kawasaki disease with cardiac complications decreased in the most recent 2 decades. Early diagnosis of Kawasaki disease as well as advances in initial treatments could explain these findings.

Environmental epidemiology of Kawasaki disease: Linking disease etiology, pathogenesis and global distribution

BACKGROUND

The pathogenesis of Kawasaki disease (KD) is commonly ascribed to an exaggerated immunologic response to an unidentified environmental or infectious trigger in susceptible children. A comprehensive framework linking epidemiological data and global distribution of KD has not yet been proposed.

METHODS AND FINDINGS

Patients with KD (n = 81) were enrolled within 6 weeks of diagnosis along with control subjects (n = 87). All completed an extensive epidemiological questionnaire. Geographic localization software characterized the subjects' neighborhood. KD incidence was compared to atmospheric biological particles counts and winds patterns. These data were used to create a comprehensive risk framework for KD, which we tested against published data on the global distribution. Compared to controls, patients with KD were more likely to be of Asian ancestry and were more likely to live in an environment with low exposure to environmental allergens. Higher atmospheric counts of biological particles other than fungus/spores were associated with a temporal reduction in incidence of KD. Finally, westerly winds were associated with increased fungal particles in the atmosphere and increased incidence of KD over the Greater Toronto Area. Our proposed framework was able to explain approximately 80% of the variation in the global distribution of KD. The main limitations of the study are that the majority of data used in this study are limited to the Canadian context and our proposed disease framework is theoretical and circumstantial rather than the result of a single simulation.

CONCLUSIONS

Our proposed etiologic framework incorporates the 1) proportion of population that are genetically susceptible; 2) modulation of risk, determined by habitual exposure to environmental allergens, seasonal variations of atmospheric biological particles and contact with infectious diseases; and 3) exposure to the putative trigger. Future modelling of individual risk and global distribution will be strengthened by taking into consideration all of these non-traditional elements.

Revisiting the role of environmental and climate factors on the epidemiology of Kawasaki disease

Can environmental factors, such as air-transported preformed toxins, be of key relevance to the health outcomes of poorly understood human ailments (e.g., rheumatic diseases such as vasculitides, some inflammatory diseases, or even severe childhood acquired heart diseases)? Can the physical, chemical, or biological features of air masses be linked to the emergence of diseases such as Kawasaki disease (KD), Henoch-Schönlein purpura, Takayasu's aortitis, and ANCA-associated vasculitis? These diseases surprisingly share some common epidemiological features. For example, they tend to appear as clusters of cases grouped geographically and temporarily progress in nonrandom sequences that repeat every year in a similar way. They also show concurrent trend changes within regions in countries and among different world regions. In this paper, we revisit transdisciplinary research on the role of environmental and climate factors in the epidemiology of KD as a paradigmatic example of this group of diseases. Early-warning systems based on environmental alerts, if successful, could be implemented as a way to better inform patients who are predisposed to, or at risk for, developing KD. Further research on the etiology of KD could facilitate the development of vaccines and specific medical therapies.

Recurrent Kawasaki disease: USA and Japan

BACKGROUND

Descriptive epidemiologic studies of recurrent and non-recurrent Kawasaki disease (KD) may identify other potentially important differences between these illnesses.

METHODS

Data from the USA and Japan, the Centers for Disease Control and Prevention (CDC) national KD surveillance(1984-2008) and the 17th Japanese nationwide survey (2001-2002), respectively, were analyzed to examine recurrent KD patients <18 years of age meeting the CDC KD case or atypical KD case definition. These patients were compared with non-recurrent KD patients.

RESULTS

Of the 5557 US KD patients <18 years of age during 1984-2008, 97 (1.7%) were identified as having had recurrent KD. Among the US Asian/Pacific Islander KD patients, 3.5% had recurrent KD, which was similar to the percentage identified among KD patients (3.5%) in the Japanese survey. Compared with non-recurrent KD patients, KD patients [with recurrent KD] were more likely to be older, fulfill the atypical KD case definition, and have coronary artery abnormalities (CAA) despite i.v. immunoglobulin (IVIG) treatment.

CONCLUSIONS

Differences in the age, race, and frequency of CAA exist between recurrent and non-recurrent KD patients. The increased association of CAA with recurrent KD suggests that more aggressive treatment strategies in conjunction with IVIG may be indicated for the second episode of KD.

Rate, associated factors and outcomes of recurrence of Kawasaki disease in Ontario, Canada

BACKGROUND

Previous studies on recurrence of Kawasaki disease (KD) have mostly been limited to Japan, which has an incidence of KD 8-10-fold higher than North America. The aim of the present study was to determine the rate of KD recurrence for patients in Ontario, to identify factors potentially associated with increased odds of recurrence, and to compare the clinical course and outcomes of index and recurrent KD episodes.

METHODS

Review was undertaken of all patients with recurrence of KD identified in Ontario, Canada, from 1995 to 2006. All patients with recurrence of KD (defined as at least three clinical signs of KD in addition to fever ≥ 5 days), presenting ≥ 14 days after the return to baseline from the index episode were included.

RESULTS

A total of 1010 patients were followed for 5786 patient-years. During this period a total of 17 recurrent episodes in 16 patients were identified at a median of 1.5 years after the initial episode (2 weeks-5 years). Rate of recurrence of KD was 2.9 episodes/1000 patient-years, which is higher than the expected annual incidence of KD in the same age group (26.2/100,000 per year). No factors associated with increased risk of recurrence were identified, perhaps due to the small number of events. Clinical course and outcomes of the index and recurrent KD episodes were similar.

CONCLUSIONS

A previous history of KD should increase the index of suspicion for future episodes of KD to allow for rapid recognition, treatment and to achieve optimal outcomes.

Kawasaki disease

Kawasaki disease is a systemic vasculitis and the leading cause of acquired heart disease in North American and Japanese children. The epidemiology, cause, and clinical characteristics of this disease are reviewed. The diagnostic challenge of Kawasaki disease and its implications for coronary artery outcomes are discussed, as are the recommended treatment, ongoing treatment controversies, concerns associated with treatment resistance, and the importance of ongoing follow up.

Epidemiology of Kawasaki disease in Asia, Europe, and the United States

Kawasaki disease (KD) is a systemic vasculitis that mainly affects children younger than 5 years. Although Dr. Tomisaku Kawasaki first reported KD over 40 years ago, the cause of the disease remains unknown. Currently, KD has been diagnosed in more than 60 countries, including those in Asia, the Middle East, Latin America, and Africa, as well as in North America and Europe. The purpose of this review is to describe the epidemiologic features of KD—particularly its incidence, seasonality, and the occurrence of coronary artery abnormalities—primarily in Japan and the United States, but also in Europe and other Asian countries.

Epidemiologic survey of Kawasaki disease in Jilin from 1999 through 2008

The epidemiologic pictures of Kawasaki disease (KD) in Jilin Province of China is still not clear. We sent a questionnaire form and diagnostic guidelines for KD to the province's 32 hospitals above the county and city level with pediatric in-patients. All patients with KD diagnosed during January 1999 through December 2008 were recruited in this survey. The incidence of KD was 1.39 to 11.07 (5.26 ± 3.97) per 100,000 children under the age of 5 years between 1999 and 2008. The ratio of male to female was 1.96 to 1. Ages at onset ranged from 58 days to 14 years. Patients under 5 years of age accounted of 88.73%. The disease occurred throughout the year, but it occurred more frequently in May to July and November. The most common cardiac abnormality was coronary artery dilatation (49.5%). Age at onset and hypoalbuminemia (<30 g/l) were selected for multivariate logistic regression equation. In conclusion, incidences of KD increased in Jilin Province. Age and gender distribution shared similarities with previous reports, and the seasonal distribution was different. Age and lower serum albumin were the most important risk factors of coronary arterial lesions (CAL) in KD. In addition, patients treated with steroids also had a possible heightened risk of contracting CAL.

Repeated systematic surveillance of Kawasaki disease in Ontario from 1995 to 2006

BACKGROUND

Rising incidences of Kawasaki disease (KD) have been reported worldwide. Reported herein are the results of 4 triennial KD surveillances conducted in Ontario.

METHODS

Between 1995 and 2006 all hospitals in Ontario were asked on 4 occasions to identify all patients with discharge diagnoses of KD and report incident cases.

RESULTS

The latest surveillance identified 697 new KD patients (100% response rate) for a total of 2378 KD patients through all 4 surveillances. Yearly incidence was 26.2/100,000 for <5 years old, 6.7/100,000 for 5-9 years old and 0.9/100,000 for 10-14 years old. KD incidence significantly increased from 1995 to 2006, although the increase seemed to plateau between the 3rd and 4th surveillance. There was an increase in the proportion of patients diagnosed with incomplete KD and a significant reduction in the rate of coronary artery abnormalities, possibly due to better disease recognition and treatment. Hospitals reporting <20 cases per surveillance were found to be more likely to report cases with incomplete KD. These patients were also less likely to be treated with i.v. immunoglobulin and aspirin but were more likely to be treated with antibiotics, suggesting uncertainties regarding diagnosis and management of KD patients in those centers.

CONCLUSIONS

The incidence of KD in Ontario is possibly one of the highest outside of Asia and has been rising since 1995. Although the most recent surveillance demonstrated improved cardiac outcomes, treatment delays or absence thereof continue to be a problem. Effective diagnosis and prompt treatment remain critical aspects of KD management.

Epidemiological investigation of Kawasaki disease in Jilin province of China from 2000 to 2008

OBJECTIVE

To investigate the epidemiological characteristics of Kawasaki disease in Jilin province of China and explore its clinical features.

METHODS

The medical records of children with Kawasaki disease hospitalised in the First Affiliated Hospital of Jilin University and Yanbian University between January, 2000 and December, 2008 were retrospectively analysed.

RESULTS

A total of 735 children with Kawasaki disease were enrolled in this study with 483 boys and 252 girls. The ratio of male to female was 1.92:1. The ages of the children at onset varied from 51 days to 12 years with a mean age of 2.8 years. The children under the age of 5 years accounted for 79.5%, but most children were 2-3 years old. Kawasaki disease occurred all the year and more frequently in both the ending of spring and the beginning of summer. Fever was the most common clinical feature and enlarged cervical lymph nodes were the smallest clinical feature. A cardiovascular lesion was found in 41.4% of these children, in whom coronary artery dilatation was the most common (26.97%). A total of 117 (18.2%) of 643 children (87.5%) receiving intravenous immunoglobulin had a non-response to gamma globulin. Of the 117 children, 66 (56.4%) had cardiovascular lesion. Kawasaki disease recurred in 19 children (2.6%).

CONCLUSION

The incidence of Kawasaki disease in Jilin province has shown an increasing tendency. The age at onset is slightly higher than that described in other reports. Kawasaki disease is the most common in both the ending of spring and the beginning of summer, and the second incidence peak occurs in autumn.

Kawasaki disease at the extremes of the age spectrum

OBJECTIVE

We sought to determine outcomes of Kawasaki disease (KD) and to explore factors associated with poor clinical outcomes for patients diagnosed outside the age range of 1 to 4 years.

METHODS

A retrospective review of data for all patients seen between January 1990 and April 2007 was performed. Patients were stratified into 5 groups on the basis of age at diagnosis.

RESULTS

A total of 1374 patients were identified; 61 (4%) were <6 months of age at diagnosis, 114 (8%) 6 months to <1 year, 854 (62%) 1 to 4 years, 258 (19%) 5 to 9 years, and 87 (6%) >9 years. Patients <1 year of age and those >9 years of age were more likely to have coronary artery abnormalities than were patients diagnosed between 1 and 4 years of age. Patients diagnosed between the ages of 5 and 9 years were at the lowest risk. Patients at both extremes of the age spectrum were more likely to present with <4 of the classic KD features, but only those <6 months or >5 years of age were at increased risk of being diagnosed >12 days after illness onset. Patients <6 months of age had lower albumin levels, and those <1 year of age had higher white blood cell and platelet counts, all of which are known predictors of coronary artery abnormalities. Patients >9 years of age were less likely to receive intravenous immunoglobulin treatment.

CONCLUSION

Outcomes for children diagnosed with KD at either extreme of the age spectrum are suboptimal, although the associated factors are different.

Prevalence of coronary artery abnormality in incomplete Kawasaki disease

BACKGROUND

The aim of the present study was to determine the prevalence of coronary artery abnormality (CAA) and other clinical features in patients with incomplete Kawasaki disease (iKD) using the data from the 17th Japanese nationwide survey of KD.

METHODS

iKD was defined as the presence of four or fewer of the principal symptoms of the Japanese diagnostic guidelines, regardless of whether the patient had CAA. A total of 15,857 cases were analyzed.

RESULTS

Among 15,857 cases, 83.9% of patients had five to six principal symptoms (complete KD: cKD), and 16.1% had iKD. The prevalence of CAA in cKD was 14.2%, and 18.4% in iKD. The prevalence of CAA in patients with four principal symptoms was 18.1%, which was higher than in cKD cases (14.2%). Although the reliability of the data has some limitations, the prevalence of CAA among patients with one to three symptoms was 19.3%. Among all CAA patients, 14% had four symptoms, and 6% had only one to three symptoms.

CONCLUSION

Incomplete KD should not be equated with mild KD. Patients with four principal symptoms were comparable to cKD with respect to CAA occurrence. In patients with one to three symptoms also, especially in those under 1 year and older than 4 years of age, other significant symptoms and laboratory findings of the guidelines are very important in making a correct and early diagnosis of iKD so as to prevent CAA.

Epidemiologic study on Kawasaki disease in Beijing from 2000 through 2004

A hospital-based survey of Kawasaki disease was performed in all 45 hospitals with in-patient beds in Beijing during the 5-year period from 2000 through 2004. A total of 1107 patients were enrolled, with an annual incidence varying from 40.9 to 55.1 per 100,000 children <5 years of age. The incidence of coronary complications was 20.6% in the acute stage, and 6.9% in the 1-2 month follow-up.

Chapter 11 Kawasaki Disease

Kawasaki disease (KD) is an acute febrile systemic vasculitis usually occurring in children younger than five years, and rarely reported in neonates and adults. This chapter discusses the epidemiology, etiology, pathogenesis, clinical manifestations, and treatments of KD. The etiology still remains unknown, although epidemiological and clinical features strongly suggest an infectious cause. Immunological abnormalities in the acute phase of the disease reflect activation of immune system and marked production of cytokines by activated cells. KD has some similarities to toxin-mediated diseases, both from a clinical and an immunological point of view. The role of one or more superantigens competent of stimulating large numbers of T cells produced by certain strains of Staphylococcus or Streptococcus is discussed in the chapter, in the context of the etiology of KD. Atypical cases are those with fever, acute surgical symptoms, or neurological manifestations as presenting signs. Medical history, physical examination, and laboratory tests including elevated white-blood cell (WBC) count, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and low hemoglobin, sodium and albumin levels may help to rule out illnesses mimicking KD. Oral or pulsed corticosteroids in children refractory to intravenous immunoglobulins (IVIG) are an alternative and safe treatment.