Associations of Whole Blood Zinc Levels with Coronary Artery Calcification and Future Cardiovascular Events in CKD Patients

Abstract

This study was conducted to compare the differences of the whole blood zinc concentration in patients with chronic kidney disease (CKD) as compared to healthy controls, and to explore the correlations of the whole blood zinc level with coronary artery calcification (CAC) and cardiovascular event (CVE) in CKD patients. A total of 170 CKD patients and 62 healthy controls were recruited. The whole blood zinc concentration was determined in using atomic absorption spectroscopy (AAS) method. The degrees of CAC were evaluated by Agatston score based on computed tomography (CT). Regular follow-up visits were performed to record the incidence of CVE, and risk factors were analyzed by COX proportional hazard model and Kaplan-Meier survival curve. There were statistically significant lower zinc levels in CKD patients than in healthy population. The prevalence of CAC was 58.82% in CKD patients. Correlation analysis showed that dialysis duration, intact parathyroid hormone (iPTH), alkaline phosphatase (ALP), 25-hydroxyvitamin D₃ (25(OH)D₃), neutrophil-lymphocyte ratio (NLR), total cholesterol (TC), and high-sensitive C-reactive protein (Hs-CRP) were positively correlated with CAC, while albumin (ALB), hemoglobin (Hb), and zinc levels were negatively associated with CAC. Further COX proportional hazard model demonstrated that moderate to severe CAC, NLR, phosphate, 25(OH)D₃, iPTH, and high-density lipoprotein (HDL) were associated with an increased risk for CVE, while zinc levels, Hb, and ALB were inversely associated with a reduced risk for CVE. Kaplan-Meier curve showed that low zinc (zinc < 86.62 μmol/L) patients and moderate to severe CAC patients had lower survival respectively. Our study found the lower levels of zinc and higher prevalence of CAC in CKD patients; the low zinc is involved in the high incidence rate of moderate to severe CAC and CVE in CKD patients.

Keywords: Cardiovascular event; Chronic kidney disease; Coronary artery calcification; Trace elements; Zinc.