Introduction: Kawasaki disease (KD) is a common pediatric autoimmune disease which may complicate with coronary artery abnormality (CAA) and coronary thrombosis. Diagnosis of incomplete KD (IKD) requires less clinical criteria of complete KD (CKD) but includes anemia for age. However, the prevalence of anemia in Northern Thai children was high. The prevalence of anemia in KD and association between clinical outcomes are scantly reported.
Objectives: The primary objective is to find prevalence and causes of anemia in KD and the secondary objective is to determine association between anemia and complications of KD.
Methods: This retrospective cross-sectional study included all children aged 0-10 years with KD in Chiang Mai University (CMU) Hospital between 2006-2019. The demographic data, clinical, laboratory and echocardiographic data for diagnosing KD were included for analysis. All patients who were investigated for the cause of anemia were analyzed in the subgroup analysis.
Results: We enrolled 317 patients with KD. One hundred and seventy-four (55%) had CKD while 143 (45%) had IKD. Most demographic, clinical and laboratory data were not different between two groups except age which was lower in patients with IKD than ones with CKD (19.2 versus 25.8 months, P < 0.001). The prevalence of anemia in patients with KD was 72%. Among 118 patients who were investigated for the causes of anemia (42% was IKD), iron deficiency anemia (IDA) was the most common cause of anemia (76%) followed by anemia for age (20%) and thalassemia (4%), respectively. Severity anemia in patients with KD was associated with CAA (P = 0.02). In univariate analysis, transferrin saturation (TSAT) < 16% and prolonged fever > 7 days were associated with CAA (P < 0.001 and < 0.001, respectively). In multivariate analysis, only prolonged fever > 7 days was significantly related to CAA [OR (Odds ratio) 0.413, 95% confidence interval (CI) 0.255 – 0.669, P < 0.001].
Conclusion: Anemia is common in patients with KD. IDA is the most common cause of anemia in this population; hence iron studies and blood film should be investigated in patients with KD who have anemia. However, prolonged fever > 7 days, not iron status, is associated with CAA.
