Influence of Latitude on the Prevalence of Kawasaki Disease: A Retrospective Cohort Study from the Taiwan National Health Insurance Database and Review of the Literature

Incidence and seasonality of Kawasaki disease in children in the Philippines, and its association with ambient air temperature

Background

Despite an unknown cause, Kawasaki disease (KD) is currently the primary leading cause of acquired heart disease in developed countries in children and has been increasing in recent years. Research efforts have explored environmental factors related to KD, but they are still unclear especially in the tropics. We aimed to describe the incidence of KD in children, assess its seasonality, and determine its association with ambient air temperature in the National Capital Region (NCR), Philippines from January 2009 to December 2019.

Methods

Monthly number of KD cases from the Philippine Pediatric Society (PPS) disease registry was collected to determine the incidence of KD. A generalized linear model (GLM) with quasi-Poisson regression was utilized to assess the seasonality of KD and determine its association with ambient air temperature after adjusting for the relevant confounders.

Results

The majority of KD cases (68.52%) occurred in children less than five years old, with incidence rates ranging from 14.98 to 23.20 cases per 100,000 population, and a male-to-female ratio of 1.43:1. Seasonal variation followed a unimodal shape with a rate ratio of 1.13 from the average, peaking in March and reaching the lowest in September. After adjusting for seasonality and long-term trend, every one-degree Celsius increase in the monthly mean temperature significantly increased the risk of developing KD by 8.28% (95% CI: 2.12%, 14.80%). Season-specific analysis revealed a positive association during the dry season (RR: 1.06, 95% CI: 1.01, 1.11), whereas no evidence of association was found during the wet season (RR: 1.10, 95% CI: 0.95, 1.27).

Conclusion

We have presented the incidence of KD in the Philippines which is relatively varied from its neighboring countries. The unimodal seasonality of KD and its linear association with temperature, independent of season and secular trend, especially during dry season, may provide insights into its etiology and may support enhanced KD detection efforts in the country.

Decreased incidence of Kawasaki disease in South Korea during the SARS-CoV-2 pandemic

Purpose

Analyzing Kawasaki disease epidemiology during the SARS-CoV-2 pandemic in South Korea using 2012-2020 National Health Insurance Service data.

Methods

The incidence of Kawasaki disease for 2012-2020 was investigated to identify changes in incidence after the start of the pandemic. National Health Insurance Service data from the Republic of Korea were used. Kawasaki disease was defined based on the International Statistical Classification of Diseases and Related Health Problems, the Tenth Revision diagnostic code (M30.3), and the intravenous immunoglobulin prescription code. Prescription history was collected for the following medications: intravenous immunoglobulin, aspirin, corticosteroids, tumor necrosis factor-α antagonist, clopidogrel, and anticoagulation drugs.

Results

The Kawasaki disease incidence per 100,000 individuals younger than 5 years was 238.9, 230.0, and 141.2 in 2018, 2019, and 2020, respectively. Regarding the incidence from 2012 to 2020, it was the highest in 2018 and decreased to 141.2 (p < 0.001) in 2020, after the start of the pandemic. In 2020, 28.3% of all patients with KD were infants, a percentage significantly higher than that of the previous year (p < 0.001). There was biphasic seasonality in the monthly Kawasaki disease incidence. The Kawasaki disease incidence was the highest in winter followed by that in early summer.

Conclusion

After the start of the pandemic, the Kawasaki disease incidence decreased, and the percentage of patients with Kawasaki disease aged <1 year increased. These findings provide support for the hypothesis suggesting an infectious trigger in Kawasaki disease.

Validation of genome-wide associated variants for Kawasaki disease in a Taiwanese case-control sample

Kawasaki disease (KD) is an acute febrile systemic vasculitis of unknown etiology that affects infants and young children. Considerable evidence supports the hypothesis that there is a genetic basis for KD susceptibility. Genome-wide association studies (GWAS) have identified several genetic variants associated with KD. This study aims to replicate three novel KD-associated single nucleotide polymorphisms (SNPs), identified by GWAS in Japanese, in a Taiwanese population. Associations between these SNPs and development of coronary artery lesions (CALs) were also investigated. The rs2254546 A/G, rs2857151 A/G, and rs4813003 C/T SNPs were genotyped in 681 children with KD and 563 ethnically-matched healthy controls using TaqMan Assay or DNA sequencing. We found rs2254546 and rs4813003 SNPs were significantly associated with KD (G allele, odds ratio [OR] = 1.54, P = 1.0 × 10^–5; C allele, OR = 1.32, P = 8.1 × 10^–4). However, no evidence for associations with CAL development was observed. Our study successfully validates associations of the rs2254546 and rs4813003 SNPs with KD in a Taiwanese population. Further functional studies of the SNPs are important in understanding the pathogenesis of KD.

Comparison of Clinical Symptoms and Cardiac Lesions in Children with Typical and Atypical Kawasaki Disease

The present study was performed to evaluate the clinical symptoms and cardiovascular complications in patients with typical and atypical Kawasaki disease (KD). This retrospective study was conducted on the medical records of 176 patients with KD for three years. The study population was divided into two groups of typical and atypical based on the KD clinical criteria. The two groups were compared in terms of demographic data, clinical symptoms, cardiac lesions, and laboratory markers. Based on the diagnostic criteria, 105 (60%) and 71 (40%) patients were diagnosed with typical and atypical KD, respectively. The mean age of the typical patients (38.16 months) was higher than that of the atypical group (24.03 months) at the time of diagnosis (p < 0.05). The results revealed no significant difference between the two groups regarding the seasonal distribution of KD onset (p = 0.422). However, the most common season for the diagnosis of the disease was spring, followed by winter. There was no significant difference between the two groups in terms of fever duration (p = 0.39). Furthermore, vomiting was more common in the atypical patients than in the typical group (p = 0.017). In terms of the cardiac lesions, ectasia (p = 0.005) and lack of tapering of the distal coronary vessels (p = 0.015) were more frequently detected in the atypical group than in the typical group. Considering the laboratory findings, thrombocytosis (p = 0.010) and anemia (p = 0.048) were more common in the atypical group, compared to those in the typical group. On the other hand, the typical group had a higher serum alanine aminotransferase level (adjusted for age) (p = 0.012) and Hyponatremia (serum sodium concentration ≤130 mmol/L) (p = 0.034). Based on the findings of the current study, the fever duration from onset to diagnosis was slightly more in atypical KD patients than in the typical group, but not statistically significant, possibly due to more timely diagnosis of atypical KD. There was no difference in coronary aneurysm between the two groups at the time of diagnosis. The atypical group had a higher frequency of coronary ectasia and lack of tapering, indicating cardiac involvement. Consequently, these conditions should be given more attention in the atypical patients. Furthermore, the higher frequency of anemia and thrombocytosis in the atypical patients can be useful for diagnosis of this kind of KD.