Clinical significance of saliva urea, creatinine, and uric acid levels in patients with chronic kidney disease

Abstract

To explore the changes and clinical significance of saliva urea, creatinine (Cr), uric acid (UA) in both healthy people and chronic kidney disease (CKD) patients, and to provide a noninvasive, quick, accurate and reliable test to diagnose kindey disease. Urea, Cr and UA in the saliva and serum collected from both healthy people and the CKD patients were measured by biochemical analyzer. We calculated the correlation coefficient of Urea, Cr and UA between the saliva and serum, compared the levels of saliva Urea, Cr and UA among CKD patients in different periods, drew the receiver operation characteristic (ROC) curve and analyzed the sensitivity and specificity of saliva Urea, Cr and UA to predict CKD patients in various periods. The concentrations of Urea, Cr and UA in both the saliva and the serum were positively correlated in healthy individuals and CKD patients (r = 0.918, 0.932, 0.840 and 0.984, 0.971, 0.920). The levels of saliva Urea, Cr and UA in the CKD patients were significantly higher than those of healthy people (P<0.05). Saliva Urea, Cr and UA concentrations of middle and late stage CKD patients were obviously higher than those of healthy people and early stage CKD patients (P<0.05). Areas under the curve (AUC) of the ROC of Urea, Cr and UA to diagnose diverse periods of CKD were 0.898, 0.897 and 0.848. The sensitivity was 0.806, 0.776 and 0.704; and the specificity was 0.968, 0.989 and 0.871. The levels of Urea, Cr and UA between the saliva and the serum are closely related. The concentration of saliva Urea, Cr and UA can reflect the renal damage, monitor kidney function of the CKD patients, and help diagnose middle to late stage CKD patients. It is a simple, nonivasive and quick method.