Objective To study the association between serum TB level and target organ damage in elderly metabolic syndrome (MS) patients.Methods Two hundred and forty-five elderly MS patients admitted to our hospital were included in this study.Their general condition was recorded,their serum TB,blood glucose,blood lipids,blood urea nitrogen and creatinine (Cr) levels were measured,and their left ventricular mass (LVM) and left ventricular mass index (LVMI) were detected by parallel echocardiography.Results Correlation analysis showed that the serum TB level was positively related with that of Cr (r=0.168,P=0.009) but not related with LVM,LVMI,serum blood urea nitrogen level,prevalence of chronic renal insufficiency and chronic kidney disease (P＞0.05).Regression analysis showed that serum TB level was an independent risk factor for urea in MS patients (OR=-0.27,95％CI:-0.48-0.06,P=0.01;OR=1.27,95％CI:0.33-2.22,P=0.01).Quantile analysis of serum TB level showed that the serum Cr level was significantly higher in Q76-100 group,Q51-75 group and Q26-50 group than in Q1-25 group (P=0.031).Conclusion Serum TB level is positively related with endogenous Cr clearance in elderly MS patients,suggesting that mildly elevated serum TB level may be a protective factor for impaired renal function in elderly MS patients.