The Application Of Saliva Urea, Creatinine And Uric Acid In Patients With Chronic Kidney Disease

Objective:1.To investigate the changes and applications of saliva Urea,Cr,UA in CKD patients.2.To explore the use of saliva Urea,Cr,UA in hemodialysis.Methods:1.1-2mL saliva and2mL blood samples were collected from both the controls and the patients before breakfast in the morning to determine the Urea concentration. The concentrations of saliva Urea,Cr,UA and serum Urea,Cr,UA were determined, the correlation of Urea,Cr,UA in saliva and serum were calculate.2. The concentrations of saliva Urea,Cr,UA were compared between CKD patients and normal subjects.3. The levels of saliva Urea,Cr,UA in patients with different CKD satges were compared.4. The diagnostic accuracy of early stage of CKD,the whole CKD,and the intermediate and advanced CKD for saliva Urea,Cr,UA were analysed by ROC curve.5. The levels of saliva Urea,Cr,UA before and after haemodialysis were compared.6. Reduction ratio (RR) of saliva and serum Urea,Cr,UA were calculated,the correlations of RRs of saliva and serum Urea,Cr,UA were analysed.Results:1. In normal subjects,the regression equation of serum and saliva Urea was Y(saliva Urea)=0.233+0.919X(serum Urea)r=0.916,P=0.000; the regression equation of serum and saliva Cr was Y(saliva cr)=0.246+0.093X(serum Cr),r=0.932,P=0.000; the regression equation of serum and saliva UA was Y(saliva UA)=3.967+0.861X(serum UA),r=0.840, P=0.000.In CKD patients, the regression equation of serum and saliva Urea was Y(saliva Urea)=-0.092+0.996X(serum Urea),r=0.984,P=0.000; the regression equation of serum and saliva Cr was Y(Saliva Cr)=-5.377+0.133X(serum Cr),r=0.971,P:=0.000; the regression equation of serum and saliva UA was Y(saliva UA)=-7.420+0.977X(serum UA),r=0.920,P=0.000.2.The levels of saliva Urea,Cr,UA in CKD patients were significantly higher than in controls(p<0.05).3. There was no difference between saliva Urea,Cr,UA in early stage of CKD patients and controls(p>0.05); the concentrations of saliva Urea,Cr,UA in intermediate and advanced CKD patients were statistically higher than in normal subjects(p<0.05), and the levels of saliva Urea,Cr,UA in intermediate CKD patients were significantly lower than in advanced CKD patients(p<0.05). 4. Area under the curve of the receiver operating characteristic (AUC) of Urea,Cr,UA to predict early CKD were0.562,0.569,0.598respectively.5. AUC of Urea,Cr,UA to predict intermediate and advanced CKD patients were0.999,0.999,0.987respectively.A cutoff point of6.89mmol/L Urea showed sensitivity=0.973,specificity=1; A cutoff point of12.62μmol/L Cr showed sensitivity=0.987,specificity=1; A cutoff point of338.35μmol/L Cr showed sensitivity=0.853,specificity=0.871.6. AUC of Urea,Cr,UA to predict CKD were0.898,0.897,0.848respectively.7. The levels of saliva Urea,Cr,UA before and after haemodialysis were significantly different(p<0.05).8. The correlation coefficient of the RR of saliva Urea,Cr,UA and the RR of serum Urea,Cr,UA were0.553,0.576,0.827respectively.Conclusions1. There were good correlations between saliva and serum Urea,Cr,UA both in patients and normal subjects.2. The levels of saliva Urea,Cr,UA were correlated with CKD patient’s condition,and they could be used in monitoring the disease.3. It is not suitable for saliva Urea,Cr,UA to help to diagnose early CKD,while they could be used as the method to screen intermediate and advanced CKD patients. 4. Serum Urea,Cr,UA could be replaced by saliva Urea,Cr,UA in the use of assessing dialysis adequacy.