The role of serum lipid in predicting coronary artery lesions and intravenous immunoglobulin resistance in Kawasaki disease: a cohort study.

OBJECTIVE: To assess the predictive value of the serum lipid profile for initial intravenous immunoglobulin (IVIG) resistance and coronary artery lesions (CALs) in patients with Kawasaki disease (KD). METHODS: This retrospective cohort study enrolled patients with KD and divided them into IVIG-responsive and IVIG-resistant groups. They were also stratified based on the presence of CALs (CALs and non-CALs groups). Clinical, echocardiographic and biochemical values were evaluated. A subgroup analysis was performed on complete and incomplete KD. Predictors of initial IVIG resistance and CALs were determined by multivariate logistic regression analysis. RESULTS: A total of 649 KD patients were enrolled: 151 had CALs and 76 had initial IVIG resistance. Low-density lipoprotein cholesterol (LDL-C) was significantly lower in the IVIG-resistant group than in the IVIG-responsive group. LDL-C and apolipoprotein (Apo) B were significantly lower in the CALs group compared with the non-CALs group. Multivariate logistic regression failed to identify the serum lipid profile (LDL-C, Apo A or Apo B) as an independent risk factor for initial IVIG resistance or CALs in KD patients. CONCLUSION: KD patients might have dyslipidaemia in the acute phase, but the serum lipid profile might not be suitable as a single predictor for initial IVIG resistance or CALs.

Investigating the comparative effect of vitamin D level with the type of complications in Henoch Schönlein purpura and Kawasaki disease.

INTRODUCTION AND OBJECTIVES: Henoch Schönlein purpura (HSP) and Kawasaki disease (KD) are two main inflammatory diseases among childhood vasculitis. Considering the anti-inflammatory effects of 25-hydroxyvitamin D3, we decided to investigate the association of serum 25-hydroxy vitamin D3 level with the type and severity of these conditions. MATERIALS AND METHODS: The present study was performed as a historical cohort of 254 affected children with KD and HSP vasculitis. The required data were extracted, using a researcher-made questionnaire from patients' electronic file, and then they were analyzed after collecting information of the patients. RESULTS: In HSP group, 54% of participants were boys. Similarly, in KD group, boys were more affected than girls. The comparative 25-hydroxyvitamin vitamin D3 level in HSP patients with and without renal involvement (P=0.02), hematuria (P=0.14), and in two groups with and without heart disease, and also with and without coronary artery dilatation in KD patients (P<0.001) were significant. DISCUSSION AND CONCLUSIONS: The findings showed that insufficient level of vitamin D3 were significantly associated with the exacerbation of complications of both diseases, and therefore it seems that vitamin D deficiency can be an effective predictive factor of severity in HSP and KD patients.

Convergence and divergence in Kawasaki disease and multisystem inflammatory syndrome in children: results from the COVASAKI survey.

OBJECTIVES: To compare Kawasaki disease (KD) and multisystem inflammatory syndrome (MIS-C) in children. METHODS: Prospective collection of demographics, clinical and treatment data. Assessment of type 1 interferon (IFN) score, CXCL9, CXCL10, Interleukin (IL)18, IFNγ, IL6, IL1b at disease onset and at recovery. RESULTS: 87 patients (43 KD, 44 MIS-C) were included. Age was higher in MIS-C compared to KD group (mean 31±23 vs. 94±50 months, p<0.001). Extremities abnormalities (p=0.027), mucosal involvement (p<0.001), irritability (p<0.001), gallbladder hydrops (p=0.01) and lymphadenopathy (p=0.07) were more often recorded in KD. Neurological findings (p=0.002), gastrointestinal symptoms (p=0.013), respiratory involvement (p=0.019) and splenomegaly (p=0.026) were more frequently observed in MIS-C. Cardiac manifestations were higher in MIS-C (p<0.001), although coronary aneurisms were more frequent in KD (p=0.012). In the MIS-C group, the multiple linear regression analysis revealed that a higher IFN score at onset was related to myocardial disfunction (p<0.001), lymphadenopathy (p=<0.001) and need of ventilation (p=0.024). Both CXCL9 and CXCL10 were related to myocardial disfunction (p<0.001 and p=0.029). IL18 was positively associated to PICU admission (0.030) and ventilation (p=004) and negatively associated to lymphadenopathy (0.004). IFNγ values were related to neurological involvement and lymphadenopathy (p<0.001), IL1b to hearth involvement (0.006). A negative correlation has been observed between IL6 values, heart involvement (p=0.013) and PICU admission (p<0.001). CONCLUSIONS: The demographic and clinical differences between KD e MIS-C cohorts confirm previous reported data. The assessment of biomarkers levels at MIS-C onset could be useful to predict a more severe disease course and the development of cardiac complications.

The effect of vitamin D status on the occurrence of Kawasaki Disease: a meta-analysis.

AIM: The relationship between vitamin D status and Kawasaki Disease (KD), as well as coronary artery lesion (CAL), has yet to be established. METHODS: A meta-analysis was conducted to assess the correlation between vitamin D status and KD, as well as the impact of vitamin D status on the progression of KD into CAL. RESULTS: The meta-analysis revealed a consistent and significant association between serum 25(OH)D level and the occurrence KD (studies N = 22; z = -3.51, P < 0.001). Patients with KD had markedly lower levels of vitamin D than healthy controls (SMD: -1.30 ng/mL, 95%CI: -2.05 to -0.55 ng/mL). CONCLUSION: The study provided evidence supporting a significant association between lower serum vitamin D levels and the occurrence of KD, particularly within the Chinese population. However, the findings did not suggest a direct impact of vitamin D on the development of CAL in KD patients.

Multisystem inflammatory syndrome in children with Kawasaki disease-like manifestations in MMA.

Not required for Clinical Vignette.

Prediction of coronary artery lesions in children with Kawasaki syndrome based on machine learning.

OBJECTIVE: Kawasaki syndrome (KS) is an acute vasculitis that affects children < 5 years of age and leads to coronary artery lesions (CAL) in about 20-25% of untreated cases. Machine learning (ML) is a branch of artificial intelligence (AI) that integrates complex data sets on a large scale and uses huge data to predict future events. The purpose of the present study was to use ML to present the model for early risk assessment of CAL in children with KS by different algorithms. METHODS: A total of 158 children were enrolled from Women and Children's Hospital, Qingdao University, and divided into 70-30% as the training sets and the test sets for modeling and validation studies. There are several classifiers are constructed for models including the random forest (RF), the logistic regression (LR), and the eXtreme Gradient Boosting (XGBoost). Data preprocessing is analyzed before applying the classifiers to modeling. To avoid the problem of overfitting, the 5-fold cross validation method was used throughout all the data. RESULTS: The area under the curve (AUC) of the RF model was 0.925 according to the validation of the test set. The average accuracy was 0.930 (95% CI, 0.905 to 0.956). The AUC of the LG model was 0.888 and the average accuracy was 0.893 (95% CI, 0,837 to 0.950). The AUC of the XGBoost model was 0.879 and the average accuracy was 0.935 (95% CI, 0.891 to 0.980). CONCLUSION: The RF algorithm was used in the present study to construct a prediction model for CAL effectively, with an accuracy of 0.930 and AUC of 0.925. The novel model established by ML may help guide clinicians in the initial decision to make a more aggressive initial anti-inflammatory therapy. Due to the limitations of external validation and regional population characteristics, additional research is required to initiate a further application in the clinic.

Protective role of forsythoside B in Kawasaki disease-induced cardiac injury: Inhibition of pyroptosis via the SIRT1-NF-κB-p65 signaling pathway.

Kawasaki disease (KD), an acute exanthematous febrile pediatric illness involving systemic non-specific inflammatory reactions in small- and medium-sized arteries, poses a significant risk of coronary artery and myocardial inflammatory injury. Developing new KD treatments with improved safety and fewer side-effects is highly desirable. Forsythoside B (FTS-B), extracted from the Forsythia suspensa plant, exerts anti-inflammatory activity by inhibiting NF-κB, which is regulated by SIRT1, the reduced expression of which is strongly associated with cardiovascular disease. However, it has yet to be established whether FTS-B influences KD-related inflammatory damage. In this study, we investigated the effects of FTS-B on inflammation in cellular and murine models of KD. Our findings revealed that KD is associated with cardiac dysfunction and inflammatory injury to myocardial and human coronary artery endothelial cells (HCAECs), resulting in a pyroptosis-feedback loop. Both cellular and KD models were characterized by reduced SIRT1 expression and increased NF-κB p65 expression. Contrastingly, the rates of pyroptosis in both murine model myocardial tissues and HCAECs were significantly alleviated in response to FTS-B treatment. Also in both models, we detected an increase of SIRT1 expression and a decrease in the expression of p65. Further examination of the protective mechanism of FTS-B using the SIRT1-specific inhibitor, EX 527, revealed that this inhibitor blocked the palliative effects of FTS-B on inflammatory injury-induced pyroptosis. These results highlight the potential utility of the SIRT1-NF-κB-p65 pathway as a therapeutic target for KD treatment and demonstrate that FTS-B can alleviate KD-induced cardiac and HCAEC inflammatory injury via inhibition of pyroptosis.

The etiologies of Kawasaki disease.

Kawasaki disease (KD) is a systemic vasculitis that affects young children and can result in coronary artery aneurysms. The etiology is currently unknown, but new clues from the epidemiology of KD in Japan, the country of highest incidence, are beginning to shed light on what may trigger this acute inflammatory condition. Additional clues from the global changes in KD incidence during the COVID-19 pandemic, coupled with a new birth cohort study from Japan, point to the potential role of person-to-person transmission of an infectious agent. However, the rising incidence of KD in Japan, with coherent waves across the entire country, points to an increasing intensity of exposure that cannot be explained by person-to-person spread. This Review discusses new and historical observations that guide us toward a better understanding of KD etiology and explores hypotheses and interpretations that can provide direction for future investigations. Once the etiology of KD is determined, accurate diagnostic tests will become available, and new, less expensive, and more effective targeted therapies will likely be possible. Clearly, solving the mystery of the etiologies of KD remains a priority for pediatric research.

Single-Cell Transcriptome Reveals Potential Mechanisms for Coronary Artery Lesions in Kawasaki Disease.

BACKGROUND: Coronary artery lesions (CALs) are the most common and major complication of Kawasaki disease (KD) in developed countries. However, the underlying immunologic mechanisms of CAL development in KD remain unclear. METHODS: Here, we conducted single-cell transcriptome analyses of 212 210 peripheral blood mononuclear cells collected from a cross-sectional cohort of 16 children, including 4 patients with KD with CALs, 5 patients with KD without CALs, 4 healthy controls, and 3 febrile controls. RESULTS: KD altered the proportion of peripheral blood mononuclear cells, including an increasing trend in inflammatory cells (megakaryocytes and monocytes) and a decreasing trend in lymphocytes (eg, CD4+ T, CD8+ T, mucosal-associated invariant T, natural killer, and γδ T cells), highlighting the potential presence of lymphopenia phenomenon in KD. Our data indicated the presence of inflammatory cytokine storm in patients with KD with CALs, caused by systemic upregulation of TNFSF13B (tumor necrosis factor superfamily member 13b), CXCL16 (C-X-C motif chemokine ligand 16), TNFSF10 (tumor necrosis factor superfamily member 10), and IL1RN (interleukin 1 receptor antagonist), mainly produced by monocytes (especially for the Mono_CD14-CD16 cluster) and megakaryocytes. We also found that myeloid cells of patients with KD, particularly in those with CALs, might play a role in vascular injury (eg, increased MMP [matrix metalloproteinase] 9, MMP17, and MMP25) and immune cell recruitment. The immune landscape of patients with KD with CALs was featured by lower exhaustion levels in natural killer cells, a high cytotoxic state in the CD8_Pro cluster, and activation of the complement system in monocytes. Additionally, the activation of B cells was more pronounced in the early stage of KD. CONCLUSIONS: Collectively, this study provides a comprehensive understanding of the roles of various immune cells and inflammatory cytokine storms in the development of CALs in KD and offers a valuable resource for identifying novel therapeutic targets for patients with KD with CALs.

Risk factors and scores for prediction of coronary artery aneurysms in Kawasaki disease: a European monocentric study.

BACKGROUND: Japanese Kawasaki disease (KD) risk scores cannot be adopted in non-Japanese patients. In North American populations a baseline coronary artery Z-score > 2 and the Son score are associated with coronary artery aneurysms (CAAs) at 4 and 8 weeks from disease onset. In European populations, the Kawanet and Kawanet-echo scores are associated with intravenous immunoglobulin resistance. This study aims to evaluate the association between KD risk scores and baseline coronary artery Z-scores with CAAs at one, two, and six months in a European population. METHODS: Historical cohort study of all the children diagnosed with KD in a tertiary care hospital in Milan, Italy, between 1st January 2015 and 31st May 2021. Univariate and multivariate (adjusting for age and corticosteroid therapy) logistic regression analyses were used to study the association between the risk scores, a baseline Z-score ≥ 2 and ≥ 2.5 with CAAs. RESULTS: Eighty-nine patients were diagnosed with KD at our Centre, and 12 were excluded based on the exclusion criteria. We included 77 patients, 51 (66%) males, and 26 (34%) females, with a median age at presentation of 27 months (IQR 13-46). A baseline Z-score ≥ 2 was correlated with CAAs at one and two-month follow-ups (odds ratio (OR) 10, 95% confidence interval (CI) 2-72, and OR 18, CI 3-357) but not at six-month follow-up. The Son score showed an association with one and two-month follow-up CAAs (OR 3, CI 1.3-7, and OR 3, CI 1.3-8) but not with a six-month follow-up. CONCLUSIONS: Patients with a baseline Z-score ≥ 2 are at higher risk for CAAs in the long term. The Son score should be tested in larger European samples. Further studies should keep the observational periods longer than 8 weeks from KD onset.

Inhibition of IL-1 Ameliorates Cardiac Dysfunction and Arrhythmias in a Murine Model of Kawasaki Disease.

BACKGROUND: Kawasaki disease (KD) is an acute febrile illness and systemic vasculitis often associated with cardiac sequelae, including arrhythmias. Abundant evidence indicates a central role for IL (interleukin)-1 and TNFα (tumor necrosis factor-alpha) signaling in the formation of arterial lesions in KD. We aimed to investigate the mechanisms underlying the development of electrophysiological abnormalities in a murine model of KD vasculitis. METHODS: Lactobacillus casei cell wall extract-induced KD vasculitis model was used to investigate the therapeutic efficacy of clinically relevant IL-1Ra (IL-1 receptor antagonist) and TNFα neutralization. Echocardiography, in vivo electrophysiology, whole-heart optical mapping, and imaging were performed. RESULTS: KD vasculitis was associated with impaired ejection fraction, increased ventricular tachycardia, prolonged repolarization, and slowed conduction velocity. Since our transcriptomic analysis of human patients showed elevated levels of both IL-1ß and TNFα, we asked whether either cytokine was linked to the development of myocardial dysfunction. Remarkably, only inhibition of IL-1 signaling by IL-1Ra but not TNFα neutralization was able to prevent changes in ejection fraction and arrhythmias, whereas both IL-1Ra and TNFα neutralization significantly improved vasculitis and heart vessel inflammation. The treatment of L casei cell wall extract-injected mice with IL-1Ra also restored conduction velocity and improved the organization of Cx43 (connexin 43) at the intercalated disk. In contrast, in mice with gain of function of the IL-1 signaling pathway, L casei cell wall extract induced spontaneous ventricular tachycardia and premature deaths. CONCLUSIONS: Our results characterize the electrophysiological abnormalities associated with L casei cell wall extract-induced KD and show that IL-1Ra is more effective in preventing KD-induced myocardial dysfunction and arrhythmias than anti-TNFα therapy. These findings support the advancement of clinical trials using IL-1Ra in patients with KD.

Thyroid hormone may predict treatment failure in Kawasaki disease.

BACKGROUND: In systemic inflammatory conditions, inflammatory cytokines can cause low thyroid hormone levels. There are no reports discussing the relation between thyroid hormone levels and response to treatment for Kawasaki disease. METHODS: We investigated 67 patients who underwent treatment in the acute phase of Kawasaki disease. We divided patients into two groups based on their response to initial intravenous immunoglobulin (IVIG) treatment: the responder group (n = 40), and the non-responder group (n = 27). The serum levels of the thyroid hormones free triiodothyronine (FT3), free thyroxine (FT4), and thyroid-stimulating hormone (TSH) were compared before and after treatment in all patients, and between responder and non-responder groups. RESULTS: The FT3, FT4, and TSH levels were low before the initial treatment and increased significantly after treatment (p < 0.05). The FT3, FT4, and TSH levels before treatment were significantly lower in the non-responder group than in the responder group (p < 0.05). Logistic regression analysis suggested that the addition of pre-treatment FT4 values to Gunma score was useful in predicting treatment failure. CONCLUSIONS: Thyroid hormone and TSH levels were lower in the non-responder group than in the responder group in the initial IVIG treatment for Kawasaki disease. This study suggests that Kawasaki disease in the acute phase is associated with low thyroid hormone levels and TSH. It is possible that these hormone levels predict response to the initial IVIG.

Risk factors and an early predictive model for Kawasaki disease shock syndrome in Chinese children.

BACKGROUND: Kawasaki disease shock syndrome (KDSS), though rare, has increased risk for cardiovascular complications. Early diagnosis is crucial to improve the prognosis of KDSS patients. Our study aimed to identify risk factors and construct a predictive model for KDSS. METHODS: This case-control study was conducted from June, 2015 to July, 2023 in two children's hospitals in China. Children initially diagnosed with KDSS and children with Kawasaki disease (KD) without shock were matched at a ratio of 1:4 by using the propensity score method. Laboratory results obtained prior to shock syndrome and treatment with intravenous immunoglobulin were recorded to predict the onset of KDSS. Univariable logistic regression and forward stepwise logistic regression were used to select significant and independent risk factors associated with KDSS. RESULTS: After matching by age and gender, 73 KDSS and 292 KD patients without shock formed the development dataset; 40 KDSS and 160 KD patients without shock formed the validation dataset. Interleukin-10 (IL-10) > reference value, platelet counts (PLT) < 260 × 109/L, C-reactive protein (CRP) > 80 mg/ml, procalcitonin (PCT) > 1ng/ml, and albumin (Alb) < 35 g/L were independent risk factors for KDSS. The nomogram model including the above five indicators had area under the curves (AUCs) of 0.91(95% CI: 0.87-0.94) and 0.90 (95% CI: 0.71-0.86) in the development and validation datasets, with a specificity and sensitivity of 80% and 86%, 66% and 77%, respectively. Calibration curves showed good predictive accuracy of the nomogram. Decision curve analyses revealed the predictive model has application value. CONCLUSIONS: This study identified IL-10, PLT, CRP, PCT and Alb as risk factors for KDSS. The nomogram model can effectively predict the occurrence of KDSS in Chinese children. It will facilitate pediatricians in early diagnosis, which is essential to the prevention of cardiovascular complications.

Right ventricular-pulmonary artery coupling is an independent risk factor for coronary artery lesions in children with Kawasaki disease.

BACKGROUND: The recognition ability of right ventricular-pulmonary artery (RV-PA) coupling for coronary artery lesions (CAL) in children with Kawasaki disease (KD) has not been well characterized. This study aimed to determine whether RV-PA coupling is an independent the risk factors for CAL in children with KD. METHODS: Between October 2021 and August 2023, RV-PA coupling was assessed in 59 KD children using the ratio between echocardiographic tricuspid annular plane systolic excursion and pulmonary artery systolic pressure (PASP). Multivariable logistic regression analysis was used to identify the independent risk factors for CAL among the demographic, clinical, laboratory and echocardiographic data. RESULTS: Twenty-nine of 59 KD children had CAL according to the diagnostic criteria of echocardiography. There were significantly different white blood cell count, C-reactive protein, erythrocyte sedimentation rate, left ventricular ejection fraction, PASP and RV-PA coupling at admission, and significantly different acute/subacute phase ratio of RV-PA coupling between KD children with and without CAL ( P  < 0.05). Multivariate logistic regression analysis identified that acute/subacute phase ratio of RV-PA coupling (OR = 26.800; 95% CI, 1.276-562.668; P  = 0.034) was an independent risk factor for CAL in children with KD. The area under receiver operating characteristic curve for the acute/subacute phase ratio of RV-PA coupling was 0.715 (95%CI: 0.624 - 0.825) to predict CAL in KD children ( P  < 0.05), with a sensitivity of 81.25% and a specificity of 62.57% at the optimal cutoff value of 0.839. CONCLUSION: The acute/subacute phase ratio of RV-PA coupling was an independent risk factor for CAL in KD children.

Initial intravenous immunoglobulin therapy without aspirin for acute Kawasaki disease: a retrospective cohort study with a Bayesian inference.

OBJECTIVE: To clarify the necessity of acetylsalicylic acid (ASA) administration combined with intravenous immunoglobulin (IVIG) therapy in the treatment of acute Kawasaki disease. DESIGN: Retrospective cohort study. SETTING: Multicentre. PARTICIPANTS: This study included 735 patients with Kawasaki disease aged ≤10 years and hospitalised between 4 and 10 days of illness in eight Japanese hospitals from January 2016 to December 2020. EXPOSURES: High-dose (HD) ASA was administered with initial IVIG to 333 patients in 6 hospitals (HD group). ASA was not administered routinely to 402 patients in the other two hospitals, and low-dose ASA was only administered when patients developed coronary artery lesions or pericardial effusion (non-HD group). PRIMARY AND SECONDARY OUTCOME MEASURES: The primary outcome was the presence of coronary artery lesions, defined as a coronary artery diameter >+2.5 SD of body surface area within 1 month of onset. The secondary outcome was responsiveness to the initial IVIG therapy. Adjusted risk ratios for the outcomes were calculated using modified Poisson regression models. Bayesian analysis was conducted to estimate the posterior probability of the treatment effect of HD ASA under several prior distributions. RESULTS: The incidence of coronary artery lesions was not significantly higher in the HD group than in the non-HD group (12/333 (3.6%) vs 15/402 (4.0%)). The proportion of non-responders to initial IVIG was similar between the two groups (HD group: 78/333 (23%); non-HD group: 83/402 (22%)). In the Bayesian analysis, considering a difference of ≤2% to be of no clinical importance, there was only a 9.3% chance of reduced risk of coronary artery lesions in the HD group compared with the non-HD group even with a strongly enthusiastic prior for HD treatment. CONCLUSIONS: Compared with HD ASA treatment, treatment without ASA in the acute phase of Kawasaki disease was not associated with increased complications from Kawasaki disease.

Kawasaki disease in neonates: a case report and literature review.

BACKGROUND: Kawasaki disease (KD) is an acute systemic vasculitis of unknown etiology that affects infants and young children but is extremely rare in neonates, especially afebrile KD. We present a case of KD without fever in a neonate and review the literature on KD in neonates. CASE PRESENTATION: A newborn female was hospitalized because her peripheral blood leukocytes increased for half a day. The admission diagnosis was considered neonatal sepsis and bacterial meningitis. She had no fever since the admission, but a rash appeared on her face by the 7th day. On day 11 after admission, there was a desquamation on the distal extremities. On day 15 after admission, ultrasound showed non-suppurative cervical lymphadenopathy. Echocardiogram revealed coronary artery aneurysms in both sides. Finally, the patient was diagnosed with incomplete KD (IKD). The follow-up echocardiogram showed that the internal diameter of both coronary arteries returned to normal three months after birth. CONCLUSIONS: Fever, rash, and distal extremity desquamation during the recovery phase are the most common symptoms of IKD. When newborns present with clinical manifestations such as rash, distal extremity desquamation and cervical lymph adenitis and with an increased peripheral blood leukocyte count and progressive increase in platelets simultaneously, the medical staff should be highly alert to the possibility of KD even without fever. The echocardiogram needs to be performed promptly. The incidence of coronary artery lesions is significantly higher if neonatal KD patients miss timely diagnosis and treatment.

Incomplete Kawasaki disease presenting with a cellulitis-like plaque: Lessons from an unusual presentation.

Kawasaki disease (KD) is an acute small to medium-vessel vasculitis that primarily affects children under the age of 5 years. The cause of KD is unknown, but it is hypothesized to be a systemic inflammatory illness triggered by infections in genetically predisposed individuals. Diagnosis of incomplete KD is made in patients with prolonged fever without a source who do not meet diagnostic criteria but have some findings consistent with KD such as elevated inflammatory markers, transaminitis, and echocardiographic findings. We present a 7-year-old boy who developed 10 days of fevers and rash that began 3 days after his first dose of hepatitis A vaccination and had notable features of a peculiar cellulitis-like plaque and peripheral eosinophilia.

Clinical prediction model: Multisystem inflammatory syndrome in children versus Kawasaki disease.

BACKGROUND: Multisystem inflammatory syndrome in children (MIS-C) is a rare but serious complication of severe acute respiratory syndrome coronavirus 2 infection. Features of MIS-C overlap with those of Kawasaki disease (KD). OBJECTIVE: The study objective was to develop a prediction model to assist with this diagnostic dilemma. METHODS: Data from a retrospective cohort of children hospitalized with KD before the coronavirus disease 2019 pandemic were compared to a prospective cohort of children hospitalized with MIS-C. A bootstrapped backwards selection process was used to develop a logistic regression model predicting the probability of MIS-C diagnosis. A nomogram was created for application to individual patients. RESULTS: Compared to children with incomplete and complete KD (N = 602), children with MIS-C (N = 105) were older and had longer hospitalizations; more frequent intensive care unit admissions and vasopressor use; lower white blood cell count, lymphocyte count, erythrocyte sedimentation rate, platelet count, sodium, and alanine aminotransferase; and higher hemoglobin and C-reactive protein (CRP) at admission. Left ventricular dysfunction was more frequent in patients with MIS-C, whereas coronary abnormalities were more common in those with KD. The final prediction model included age, sodium, platelet count, alanine aminotransferase, reduction in left ventricular ejection fraction, and CRP. The model exhibited good discrimination with AUC 0.96 (95% confidence interval: [0.94-0.98]) and was well calibrated (optimism-corrected intercept of -0.020 and slope of 0.99). CONCLUSIONS: A diagnostic prediction model utilizing admission information provides excellent discrimination between MIS-C and KD. This model may be useful for diagnosis of MIS-C but requires external validation.