Big Data Analyses Using Health Care Records Can Reveal Epidemiologic Features of Kawasaki Disease in Japan: A Study Based on the National Database of Health Insurance Claims

BACKGROUND: Kawasaki disease (KD) is a vasculitis syndrome of unknown etiology and the leading cause of acquired heart disease in children in developed countries. The Japanese Nationwide Survey of Kawasaki Disease (JNSKD) in Japan has provided valuable epidemiological data since 1970, but has inherent limitations. We aimed to evaluate the utility of the National Database of Health Insurance Claims (NDB) for describing the epidemiologic features of KD. METHODS: We conducted retrospective cohort study compared NDB data (2013-2019) against JNSKD data for the same period. We analyzed demographic characteristics, temporal and geographic distributions, treatment modalities, and cardiac complications. RESULTS: NDB identified 120,391 KD patients (2013-2019), with JNSKD estimated to cover 94.0% of cases. Demographic characteristics showed strong concordance between datasets (male-to-female ratios: 1.32 vs 1.33; similar age distributions). Initial IVIG administration rates were highly similar (93.74% vs 93.85%). Incomplete KD was significantly underestimated in NDB (8.07% vs 19.48%). NDB revealed adjunctive therapies including urinastatin and tracked increasing infliximab use. Cardiac complication detection in NDB showed limited sensitivity for mild abnormalities (overall 5.0% vs 7.33%). NDB showed higher recorded rates of giant aneurysms (0.53% vs 0.17%) and myocardial infarction (0.15% vs 0.01%). CONCLUSIONS: The NDB provides a valid, complementary data source for KD epidemiological research with near-complete population coverage. While limitations exist for identifying disease subtypes and cardiac complications, its detailed treatment data offer significant advantages for nationwide surveillance and health policy development.