BackgroundTo explore the application value of syndecan-1 (SDC-1) in the diagnosis of coronary artery lesions (CALs) in Kawasaki disease (KD) patients and the correlation of multiple laboratory indicators in KD patients.Methods86 pediatric Kawasaki disease (KD) patients and 52 healthy controls admitted from January 2018 to December 2023 were retrospectively analyzed. Venous blood samples from KD patients were analyzed for white blood cells (WBC), platelets (PLT), C-reactive protein (CRP), interleukin-6 (IL-6), syndecan-1 (SDC-1), coagulation parameters, and lipid profiles. Correlations between these laboratory indicators were assessed. Receiver operating characteristic (ROC) curve analysis determined the diagnostic value of SDC-1 for coronary artery lesions (CALs) in KD patients. SDC-1 levels were further compared across different CAL severity groups.ResultsThe levels of ALT, AST, WBC, PLT, CRP, IL-6, and SDC-1 in the KD group were significantly higher than those in the control group (P < 0.05). Coagulation function analysis showed that APTT, TT and FIB levels were significantly increased in the KD group compared with the control group (P < 0.05). Lipid profile analysis revealed that TC, HDL-C, and ApoA1 were significantly decreased, whereas TG, LDL-C, and ApoB100 were significantly increased in the KD group (P < 0.05). Refractory KD patients exhibited significantly higher levels of ALT, AST, SDC-1, CRP, WBC, and TG compared to responsive KD patients (P < 0.05). Correlation analysis indicated a strong positive correlation between PLT and LDL-C (r = 0.227, P = 0.035) and between IL-6 and TG (r = 0.491, P = 0.000), while CRP was negatively correlated with ApoA1 (r = -0.265, P = 0.014). Among the 86 KD patients, 41 (47.67%) developed CALs, with 19 classified as mild, 15 as moderate, and 7 as severe. For predicting CALs among KD patients, the threshold of SDC-1 was identified as 5.5 ng/ml, with a sensitivity of 70.7%, specificity of 64.4%, positive predictive value of 65.91%, negative predictive value of 69.05%, and an AUC of 0.762 (95% confidence interval 0.662–0.861, P < 0.001). SDC-1 levels significantly differed among the CAL severity groups (P = 0.008), with higher levels observed in moderate compared to mild CALs, and in severe compared to moderate CALs.ConclusionIn conclusion, SDC-1 has strong clinical value in the diagnosis of CALs in KD patients, and there is a close relationship between the levels of inflammatory factors, coagulation function and lipid levels in KD patients.