Abstract: 【Abstract】Objective To investigate the relationship between Cathepsin K level and cardiovascular disease (CVD) death in maintenance hemodialysis (MHD) patients. Methods From Jan 2017 to Dec 2019, 96 MHD patients in the blood purification center of Lianyungang first people's hospital were selected as the research objects (MHD group, n=96). Another 96 healthy people in the physical examination center were selected as the control group (healthy control group, n=96). The serum cathepsin K level was detected by electrochemiluminescence. The correlation between serum cathepsin K level and clinicopathological features and laboratory parameters was analyzed by Pearson correlation. The risk factors of CVD death were analyzed by logistic regression. Results The serum Cathepsin K level of MHD group was 280.75±36.84 ng/L, which was significantly higher than that in healthy control group (112.95±20.14 ng/L，t=39.158, P＜0.001). The serum Cathepsin K level of MHD survival group was 224.56±38.95 ng/L, which was significantly lower than that in CVD death group (417.21±35.99ng/L, t=23.273, P＜0.001). The serum Cathepsin K level was negatively correlated with diabetes and white blood cell count (r=-0.324, P=0.011; r=-0.311, P=0.009), and positively correlated with parathyroid hormone, alkaline phosphatase and C-reactive protein(r=0.411, P=0.002; r=0.487, P＜0.001; r=0.418, P=0.002). Low hemoglobin level and high Cathepsin K level were independent risk factors of CVD death in MHD patients (OR= 1.125, 95% CI:1.014~1.944, P=0.041; OR=2.012, 95% CI:1.411~6.254, P=0.003). Conclusion The serum Cathepsin K level is significantly increased in MHD patients and CVD death patients, and Cathepsin K is a potential biomarker of CVD death in MHD patients.

Key words: Maintenance hemodialysis, Cathepsin K, Cardiovascular disease, Biomarkers