Abstract: Objective　To investigate the serum expression levels of vitamin K2 (VK2), runt related transcription factor 2 (Runx2) and their relationship with cardiovascular calcification in patients with stage Ⅲ-Ⅴ non dialysis chronic kidney disease (CKD). Methods　A total of 149 patients with stage Ⅲ-Ⅴ CKD who did not receive dialysis were selected. According to the clinical stage, patients were divided into the stage Ⅲ group (58 cases), the stage Ⅳ group (52 cases) and the stage Ⅴ group (39 cases). In addition, according to the cardiovascular calcification, the patients were divided into the calcification group (42 cases) and the non calcification group (107 cases). The general data of all patients were collected. Serum levels of phosphorus, calcium, creatinine (Cr) and cystatin C (Cys C) were detected by automatic biochemical analyzer. The serum expressions of VK2 and Runx2 were detected by enzyme-linked immunosorbent assay kit. Results　The levels of phosphorus, Cr, Cys C, Runx2 and cardiovascular calcification rate were increased gradually in the stage Ⅲ group, the stage Ⅳ group and the stage Ⅴ group, and levels of calcium and VK2 were decreased gradually, and the difference was statistically significant between groups (P＜0.05). The levels of phosphorus, Cys C and Runx2 were higher in the calcified group than those in the non calcified group, and the level of VK2 was lower than that in the non calcified group (P＜0.05). Multivariate analysis showed that the high expression levels of phosphorus and Runx2 were the risk factors of cardiovascular calcification in patients with CKD, while the high expression of VK2 was the protective factor of cardiovascular calcification in patients with CKD (P＜0.05). ROC analysis showed that serum levels of VK2, Runx2 and phosphorus had high evaluation value for patients with CKD complicated with cardiovascular calcification, and the areas under the curve were 0.843 (95%CI: 0.773-0.913), 0.819 (95%CI: 0.749-0.889) and 0.797 (95%CI: 0.726-0.868) respectively. Conclusion　The serum level of VK2 is decreased with the increase of stage, and the level of Runx2 is increased with the increase of stage in patients with stage Ⅲ-Ⅴ non dialysis CKD. Both VK2 and Runx2 are closely related to the situation of cardiovascular calcification.

Key words: vascular calcification, vitamin K2, chronic kidney disease, Runt-related transcription factor 2