Abstract: Objective  To investigate the correlation between serum vitamin K2 (VitK2) and abdominal aortic calcification (AAC) in patients with chronic kidney disease (CKD) at stage 3～5, and to analyze the risk factors for vascular calcification (VC), so as to provide new ideas for diagnosis, treatment, and control of VC.  Methods   A total of 178 CKD patients at stage 3～5 and hospitalized in the Department of Nephrology, Tianchang People’s Hospital from September 2020 to May 2023 were recruited as the study subjects. Lumbar lateral X-ray examination was used to determine AAC, by which patients were assigned into calcification group or control group. VitK2 and its related indexes were compared between the two groups. Binary logistic regression was used to analyze the independent influencing factors for AAC. The correlation between VitK2 and AAC was then discussed.  Results  There were 104 cases (59 males and 45 females) in calcification group, with an average age of 67.58±11.90 years, and there were 74 cases (54 males and 20 females) in control group, with an average age of 52.86±14.17 years. The overall calcification rate was 58.43%. Compared with control group, estimated glomerular filtration rate (eGFR) (Z=1.974, P=0.041), VitK2 (Z=3.765, P=0.025) and serum uric acid decreased (t=2.373, P=0.022), and serum 25-hydroxyvitamin D3 (Z=2.077, P=0.042) and CRP (Z=3.214, P=0.001) increased in calcification group. Multivariate regression showed that VitK2 (OR=0.425, 95% CI:0.146～0.617, P=0.005), eGFR (OR=0.854, 95% CI:0.814～0.886, P=0.023) and age (OR=1.123, 95% CI:1.075～1.176, P=0.001) were the independent influencing factors for AAC. The equation from regression model was ln[P/(1-P)]=-2.657+0.122×age-0.166×eGFR-0.866×VitK2. Correlation analysis showed that AAC was negatively correlated with VitK2 (r=-0.253, P=0.034) and eGFR (r= -0.263, P=0.005), and was positively correlated with age (r=0.343, P=0.001), CRP (r=0.241, P=0.001) and intact parathyroid hormone (r=0.191, P=0.011).   Conclusion   Serum VitK2 is correlated with AAC. Serum VitK2, eGFR and age are the independent influencing factors for AAC. Serum VitK2 level can be used as an important reference marker for prediction of VC.

Key words: Vitamin K2, Vascular calcification, Chronic kidney disease, Hemodialysis, Peritoneal dialysis