Can salivary urea and creatinine levels be used to follow up sudanese patients with renal failure under hemodialysis as accurately as Serum creatinine and urea levels?

Background: The uses of saliva markers have clear benefits than serum , the reason of this benefits saliva collection is a noninvasive, easy, and cheap. Objectives: The aim of this study was to compare the levels of urea and creatinine in plasma and saliva of Sudanese patients with renal failure under hemodialysis, and to investigate the potentiality of determination of saliva urea and creatinine levels instead of using plasma. Participants and Methods: A case-control study was conducted from May to Jun2018, involving fifty Sudanese Patients who had been diagnosed ofrenal failure, and had been admitted to Omer Alhag Musa Hospital, in GazeraState as cases(17 of them were females and 33 were males); and fifty healthy individuals were recruited as controls (16 of them were females and 34 of them were males), age ranged from 20 to 70 years in both groups, blood samples and saliva were collected and the levels of urea and creatinine were measured, using BioSystem (Apel/AP-101). Data analysis was carried out, using SPSS version, 21. Mean values werecalculated and independent t-test was used to compare mean values in case versus control group and Pearson’s correlation was used to find the relationship between urea and creatinine levels in serum and saliva. Results: There were significant increase in the mean levels of plasma urea (mean ± SD: 179.9 ± 51.4 vs. 37.00 ± 253 mg/dL; p = 0.001) and creatinine (9.40 ± 2.38 versus 0.97 ± 0.6 mg/dL; p = 0.001) in patients with renal failure when compared to control group. Also there were a significant increase in the mean levels of saliva urea(214.1 ± 64.1 vs. 27.2 ± 27.5 mg/dL; p = 0.001) and creatinine (12.00 ± 3.89 vs. 1.01 ± 0.7 mg/dL; p = 0.001) in patients with renal failure when compared to control group.The result shows a significant positive correlation between plasma urea and saliva urea in patients with renal failure (r = 0.529; p = 0.001), also there wasa significant positive correlation between plasma urea and saliva urea in patients with renal failure (r=0.579; p =0.001).The plasma urea showed sensitivity of 99.9%, and specificity of 99.8% while the salivary urea showed sensitivity of 98% and specificity of 98%, but the plasma and saliva creatinine showed same sensitivity of 97% and same specificity of 97%. Conclusion: Sudanesepatients with renal failure under hemodialysis had increased levels of urea and creatinine in saliva and plasma. Sensitivity and specificity of saliva urea and creatinine levels are comparable to those of plasma.