Introduction:
Kawasaki disease (KD) is a systemic vasculitis of unknown etiology and the leading cause of acquired heart disease in children under five years of age in industrialized countries, primarily due to the development of coronary artery aneurysms (CAA). Several studies have proposed the existence of distinct clinical–laboratory phenotypes within KD, associated with different inflammatory profiles and varying risks of complications. Validation of these subgroups in independent cohorts could contribute to improved prognostic stratification and personalized management.
Methods:
A descriptive study was conducted including patients with KD enrolled in the Spanish KAWA-RACE registry, a prospective cohort from 2018 to 2025. Patients were classified into phenotypic subgroups based on clinical and laboratory characteristics: hepatic involvement (elevated alanine aminotransferase, gamma-glutamyl transferase, and total bilirubin), neutrophilia (leukocytosis with elevated neutrophil count and C-reactive protein), cervical lymphadenopathy (elevated erythrocyte sedimentation rate, C-reactive protein, leukocytosis, and thrombocytosis), and early age at disease onset (younger age, reduced neutrophil count, elevated C-reactive protein, and thrombocytosis). Associations between these phenotypes and relevant clinical outcomes—including coronary artery aneurysms, intravenous immunoglobulin (IVIG) resistance, shock presentation, and hematological abnormalities—were analyzed. Odds ratios (OR) with 95% confidence intervals were calculated.
Results:
A total of 101 patients were analyzed and classified into phenotypic subgroups. The hepatic involvement group (60 patients, 59.4%) showed a higher tendency toward the development of coronary artery aneurysms and IVIG resistance. The neutrophilia subgroup (25 patients, 24.7%) exhibited an increased likelihood of shock presentation. The cervical lymphadenopathy subgroup (5 patients, 5%) showed higher OR associated with lower age-adjusted hemoglobin z-scores. In the early-onset age subgroup (11 patients, 10.9%), a lower tendency toward IVIG resistance and a higher probability of developing coronary artery aneurysms were observed.
Conclusions:
Phenotypic subgroups of KD demonstrated clinical trends consistent with those previously reported, although statistical significance was not reached, likely due to the small size of some subgroups. These findings support the biological plausibility of phenotypic stratification in KD and underscore the need for larger studies to confirm its prognostic value and potential impact on clinical decision-making.