Abstract
BACKGROUND: Despite the potential association between Kawasaki Disease (KD) and coronavirus disease 2019 (COVID-19), real-world clinical associations remain unclear. We aimed to investigate the association between KD and COVID-19 using a Japanese claims database. METHODS: Using a Japanese claims database, we identified patients diagnosed with COVID-19 between January 1, 2020, and December 31, 2022 and conducted the following two analyses: a nested case-control study wherein each KD case was matched 1:4 to controls (without KD), and conditional logistic regression analyses were used to calculate odds ratios (ORs) for COVID-19 exposure in the previous 1-30, 31-60, and 61-90 days. In the self-controlled case-series (SCCS) analysis, the observation comprised the 120 days before and after COVID-19 diagnosis (Day 0). We calculated the incidence rate ratio (IRR) of three risk periods (Days 1-30, 31-60, 61-90) after Day 0 compared with the control periods. RESULTS: Nested case-control analysis matched 134 cases with 536 controls. COVID-19 exposure was identified in 26.1% (35/134) of cases and 7.3% (39/536) of controls during the previous 1-30 days (adjusted OR 7.8, 95% CI 3.2-19), and in 18.7% (25/134) and 8.8% (47/536) during the previous 31-60 days (adjusted OR 3.6, 95% CI 2.0-6.5). SCCS analysis included 124 patients, revealing elevated IRRs on Days 1-30 (95% CI: 11 [6.0-20]), and 31-60 (6.9 [3.6-13]) after COVID-19 diagnosis. CONCLUSION: The present study found that COVID-19 was associated with the development of KD.