Diagnostics
Yuri Matsubara, MD, MPH, PhD
Assistant Professor
Jichi Medical University
Shimotsuga, Tochigi, Tochigi, Japan
Background: Kawasaki disease decreased in number amid the COVID-19 pandemic through the 26th nationwide survey in Japan (from January 2019 to December 2020). However, the association between COVID-19 and KD is unclear. Similarly, the clinical features of those with multisystem inflammatory syndrome (MIS-C), some of which showed clinical overlap with KD, are unknown because of the lack of large studies in Japan. In this study, we aim to reveal the difference in epidemiological/clinical features between KD and MIS-C, using the latest 27th nationwide survey in Japan.
Methods: Using the 27th nationwide survey (from January 2021 to December 2022), we categorized patients with KD into three groups: 1) SARS-CoV2 (-) KD, 2) SARS-CoV2 (+) KD, and 3) MIS-C. We examined the number of patients in each group, their age, clinical diagnostic category, initial therapy, and the frequency of cardiac complications among the three groups.
Results: The total number of patients was fewer (n=21,930) than that of the previous survey (n=28,520 in the 26th survey). Among 21,930 patients, 19,527 were analyzed in this study, including SARS-CoV2 (-) KD (n = 19,059), SARS-CoV2 (+) (n=320), and MIS-C (n=151). We excluded the patients (n=2,403) without any information of COVID-19 infection. The peak of SARS-CoV2 (-) KD was observed in August and January. On the other hand, the SARS-CoV2 (+) KD was observed soon after the COVID-19. The median ages were 2y, 2y 6m, and 7y 10m, respectively. Sixty-three percent of patients with MIS-C met the complete KD criteria (5 or 6 symptoms out of 6 principal signs, including fever). Combined steroid therapy with IVIG was performed at 11.2%, 12.5%, and 31.8%, respectively. Small cardiac aneurysms (Z score 2.5-4.9) in acute stage were 5.6 %, 4.7%, and 3.3 % and cardiac sequelae were noted in 1.4%, 1.3%, and 0.7%, respectively.
Conclusions: Even during the pandemic, SARS-CoV2 (-) KD showed the same trend in occurrence as traditional KD. On the other hand, SARS-CoV2 (+) KD shared the same peak with COVID-19, suggesting that COVID-19 could become trigger KD in children. The higher number of MIS-C in Japan met the complete KD criteria than other countries. Cardiac aneurysms could also occur in those with MIS-C as much as in those with KD.