Hypovitaminosis D and leukocytosis to predict cardiovascular abnormalities in children with Kawasaki disease: insights from a single-center retrospective observational cohort study

Introduction: An aberrant immune response involving yet unidentified environmental and genetic factors plays a crucial role in triggering Kawasaki disease (KD). Aims: To assess general and laboratory data at the onset of KD in a single-center cohort of children managed between 2003 and 2023, and retrospectively evaluate any potential relationship with the development of KD-related cardiovascular abnormalities (CVA). Patients and methods: We took into account a total of 65 consecutive children with KD (42 males, median age: 22 months, age range: 2-88 months) followed at the Department of Life Sciences and Public Health in our University; demographic data, clinical signs, and laboratory variables at disease onset, before IVIG infusion, including C-reactive protein, hemoglobin, white blood cell (WBC) count, neutrophil count, platelet count, aminotransferases, natremia, albumin, total bilirubin, and 25-hydroxyvitamin D. Results: Twenty-one children (32.3% of the whole cohort) were found to have echocardiographic evidence of CVA. Univariate analysis showed that diagnosis of KD at <1 year or >5 years was associated with CVA (p=0.001 and p=0.01, respectively); patients with CVA had a longer fever duration, and mostly presented atypical or incomplete presentations. Interestingly, all patients with CVA had lower levels of vitamin D (less than 30 mg/dl, p=0.0001) and both higher WBC and higher neutrophil counts than those without CVA (p=0.0001 and p=0.01, respectively). Moreover, blood levels of albumin were significantly lower in KD patients with CVA compared to those without (11/21, 52% versus 13/44, 30%, p=0.02). Multiple logistic regression with correction for sex showed that serum vitamin D <30 ng/ml, WBC count >20.000/mm3, and age >60 months at KD onset were the only independent factors statistically associated with CVA. Conclusions: Hypovitaminosis D, WBC count over 20.000/mm3, and age above 5 years at KD onset have emerged as independent factors statistically associated with the occurrence of CVA.