Age-Dependent Variations in Clinical Presentation, Laboratory Parameters, and Coronary Outcomes in Kawasaki Disease: A 10-Year Retrospective Cohort Study of 480 Pediatric Patients in Eastern China

Objective: This study investigated the age-dependent clinical characteristics of Kawasaki disease (KD) in pediatric patients and assessed the influence of age on disease presentation and outcomes. Methods: A retrospective analysis was conducted of 480 children diagnosed with KD who were admitted to Hangzhou First People's Hospital between 2013 and 2022. Subjects were stratified into two cohorts based on age: <2 years and 2-14 years). Demographic data, clinical manifestations, laboratory parameters, comorbidities, and coronary artery abnormalities were comprehensively evaluated across the age groups. Results: Time from symptom onset to diagnosis was significantly prolonged in the older cohort (z=-2.70, P=0.007). The incidence of cervical lymphadenopathy was markedly higher in older children (χ²=15.12, P<0.001), while peripheral extremity changes were significantly less frequent (χ²=5.79, P=0.016). The younger cohort exhibited significantly elevated platelet counts, alanine aminotransferase, and NT-proBNP levels compared to older patients (z=-3.57, P<0.001; z=-2.39, P=0.02; z=-3.59, P<0.001, respectively). Coronary artery dilatation and aneurysm formation occurred more frequently in younger patients (z=7.70, P=0.006; z=14.63, P<0.001). However, coronary artery recovery rates following intravenous immunoglobulin therapy showed no significant inter-group differences (P>0.05). Conclusions: The clinical presentation of KD demonstrates significant age-dependent variation. Clinicians should maintain a high index of suspicion for KD in older children presenting with fever and cervical lymphadenopathy. In younger patients with KD, close monitoring of hepatic function, platelet counts, and NT-proBNP is warranted. The elevated risk of coronary artery complications in younger patients underscores the importance of prompt diagnosis and intervention to optimize clinical outcomes.