Free 25-Vitamin D Is Correlated With Cardiovascular Events In Prevalent Hemodialysis Patients

Background: Cardiovascular disease is the most common cause of mortality in hemodialysis patients.Chronic kidney disease-mineral and bone disorder is a common complication of hemodialysis patients.Chronic kidney disease-mineral and bone disorder promotes arteriosteogenesis.Vitamin D plays an important role in the stabilization of calcium and phosphorus.Arteriosteogenesis is the main pathological basis of cardiovascular disease.Therefore,accurately and effectively measuring the level of vitamin D is very important for hemodialysis patients.There have been studies on total 25-hydroxyvitamin D and cardiovascular events,but the conclusions are not consistent.Total vitamin D is not stable under the influence of many factors,while free vitamin D is relatively stable and is the biologically active form of vitamin D.Free vitamin D may have a better and stable correlation with the morbidity and mortality of cardiovascular events and have more clinical value.The goal of our current study was to investigate the relation between blood concentrations of free 25-hydroxyvitamin D with cardiovascular events in end-stage CKD patients on hemodialysis,because this is unknown so far.Method: We measured free 25-hydroxyvitamin D levels in 117 prevalent hemodialysis patients in September and recorded the number of cardiovascular events defined as hospitalization due to episodes of acute coronary syndrome and stroke during the follow-up for 6 months.Fourteen events occurred during the observation period,which were defined as event group.103 patients without cardiovascular events were defined as non-event group.The baseline data of the two groups were analyzed by statistical analysis.The correlation between free 25-hydroxyvitamin D,laboratory /clinical parameters and cardiovascular events was analyzed by spearman correlation.The risk factors were analyzed by logistic regression analysis.Result: By comparing the clinical baseline data of the two groups,there were significant difference in the natural log transformation of free vitamin D(P = 0.015),free 25-hydroxyvitamin D(P = 0.015),and lymphocyte count(P = 0.023).In patients without any cardiovascular events,the free 25-hydroxyvitamin D levels were significantly higher as compared to those with cardiovascular events(patients without events: 5.68(4.37-9.27)pg/mL;patients with events: 4.74(3.46-5.37)pg/mL,P =0.015).This finding remained stable after multiple regression analysis considering confounding factors such as age,time on dialysis,diabetes,hypertension and coronary atherosclerotic heart disease.In spearman correlation,only the natural log transformation of free vitamin D(P = 0.015),free 25-hydroxyvitamin D(P = 0.015),serum urea(P = 0.047)were correlated with cardiovascular events.Conclusion: In conclusion,our study shows that free 25-hydroxyvitamin D serum concentrations are independently associated with major cardiovascular events in CKD patients on dialysis.