Clinical Characteristics and Risk Assessment of Kawasaki Disease according to Age Group

We aimed to evaluate the differences in clinical characteristics and risk factors for intravenous immunoglobulin (IVIG) resistance and coronary artery dilatation (CAD) in patients with Kawasaki disease (KD) according to age. We collected data of patients between 2009 and 2019 and divided them into three groups according to age at diagnosis. A total of 644 patients were enrolled: 168 (26.1%) in the younger age (≤ 12 months of age), 407 (63.2%) in the usual age (13–60 months of age), and 69 (10.7%) in the older age group (> 60 months of age). The younger age group had fewer typical symptoms and a higher incomplete KD incidence than the usual age group. The differences in the incidence of IVIG resistance and CAD among age groups were statistically insignificant, except for two cases of giant aneurysms in the older age group. The risk factors for IVIG resistance were long total fever duration and high neutrophil-to-lymphocyte ratio (NLR) in the younger age group, long total fever duration and short fever duration before admission in the usual age group, and high NLR in the older age group. The risk factors for CAD were long total fever duration and short fever durations before admission in the younger age group, and long total fever duration, many recurrences, and IVIG resistance in the usual age group. Clinicians must understand the age-related differences not only in the clinical characteristics but also the risk factors of patients with KD.