Comparison of Changes in Urea and Electrolyte Levels in Saliva and Serum of ‎Patients Before and after Hemodialysis‎

Download PDF

Background: One of the methods for evaluating the efficiency of hemodialysis is measurement ‎of serum urea levels before and after dialysis. Because urea is also secreted in the saliva, ‎finding a relation between serum and salivary urea levels can facilitate this evaluation and ‎decrease the frequency of blood sampling. The purpose of this study was to compare changes in ‎the biochemical parameters in serum and saliva in patients before and after hemodialysis.‎ Methods: In this descriptive-analytic study, 43 consenting patients undergoing hemodialysis ‎who met the inclusion criteria were examined. Venous blood was collected before and after ‎hemodialysis. Whole saliva was collected by spitting into sterile tubes for 5 min before and ‎after hemodialysis. The samples were sent to a laboratory for analysis of urea, creatinine, ‎potassium, calcium and phosphorous. The results were compared and analyzed using SPSS17 ‎and p < 0.05 was considered significant.‎ Results: Serum urea, creatinine, potassium and phosphorous levels decreased significantly ‎after hemodialysis in comparison with pre-dialysis levels (p < 0.001). In saliva urea, creatinine ‎and potassium levels decreased significantly after hemodialysis (p < 0.001), but the decrease in ‎calcium and phosphorous were not significant. A significant positive correlation was found ‎between the serum and salivary urea reduction ratio (r = 0.724).‎ Conclusion: It can be concluded that the urea reduction rate in saliva reflected the urea ‎reduction rate of serum, but there was no significant correlation between changes in other ‎parameters in the saliva and serum; however, more studies are needed to develop a practical ‎use of salivary analysis for evaluating hemodialysis patients‎‎‎.