Kawasaki disease (KD) is an acute multisystem vasculitis that is the leading cause of acquired heart disease in children in developed countries [1]. Multinational evidence shows that the incidence of KD ranges from 20 to 370 per 100,000 children below five years of age [1]. It is projected that one in four affected children will experience coronary artery lesions if allowed to proceed uncurbed [1,2], placing a heavy burden on individuals and the society. In certain cases, KD causes long-lasting impairment of vascular health [3]. However, post-treatment clinical evaluations are not periodically performed in large centers or cohorts, and the follow-up periods are not long enough to capture sufficient events, resulting in adverse events that are not fully understood. Therefore, it is important to monitor promising interval markers and external manifestations after previous KD to facilitate timely intervention and reduce the disease burden.

Emerging research has focused on dyslipidemia and vascular abnormalities in individuals with a history of KD [[4], [5], [6]], the findings remain inconsistent. For instance, Chien et al. showed significantly lower circulating high-density lipoprotein cholesterol (HDLC) levels in Chinese patients with KD than in age- and sex-matched healthy controls 9.79 years post-onset, irrespective of the presence of coronary artery lesions (CAL) [7]. Conversely, Ishikawa et al. found no alterations in the lipid profile of children assessed 3.3 years after KD [8]. In individuals over 10 years after KD onset, Noto et al., Tobayama et al., and Niboshi et al. consistently observed normal total cholesterol (TC) levels [[9], [10], [11]], whereas Gupta-Malhotra et al. demonstrated elevated TC levels compared with controls [12]. However, Mori et al. reported increased flow-mediated dilation (FMD) [13], while Borzutzky et al. reached the opposite conclusion in an American cohort [14]. Other studies revealed comparable carotid intima-media thickness (CIMT) between individuals with and without prior KD [4,15, 16]. The reasons for these discrepant results are multifaceted, possibly due to the enrollment of genetically heterogeneous groups, diverse durations of previous KD, different age and sex compositions, and lack of statistical power due to limited sample sizes. A practical approach to shed light on these possible reasons is to perform a meta-analysis, a powerful tool that can increase the amount of individual data available to answer a debatable research question, enhance the reliability of the results, and explore possible sources of between-study heterogeneity. Few studies have meta-analytically addressed the possible connection between dyslipidemia and vascular structure and functional abnormalities in children previously diagnosed with KD.

In the present study, we aimed to fill this knowledge gap by conducting a comprehensive meta-analysis and pooling the results of observational studies that compared lipid levels and vascular ultrasound indices between individuals with previous KD and normal controls. Meanwhile, the incidence of cardio-cerebrovascular events was also synthesized.