Comparative Analysis of Salivary and Serum Urea and Creatinine Levels in Pre- and Post-Dialysis Patients with Renal Disease: Original Research

Abstract

Introduction:Patients with chronic kidney disease (CKD) on hemodialysis undergo major biochemical shifts. Non-invasive saliva testing could supplement blood investigations but needs validation.

Aim:To compare salivary and serum urea, creatinine, sodium, potassium, and phosphate levels in CKD patients before and after hemodialysis, and assess their correlation.

Materials and Methods:This cross-sectional study included 50 CKD patients on maintenance hemodialysis for over one year. Paired saliva and blood samples were collected pre- and post-dialysis. Biochemical markers were analysed using standard methods. Data were analysed using SPSS v21. Paired t-tests compared values; Pearson’s correlation tested associations.

Results:Salivary urea, creatinine, potassium, and phosphate decreased significantly post-dialysis (P < 0.001); sodium showed an insignificant rise. All serum parameters declined significantly (P < 0.001). The percentage decrease was larger in serum than saliva for urea, creatinine, sodium, and potassium, but phosphate fell more in saliva. Changes were significantly higher in serum than saliva for most markers (P < 0.001). No significant correlations were found among salivary parameters. A significant inverse correlation was seen between serum creatinine and sodium (r = –0.32, P < 0.05) and a direct one between serum creatinine and phosphate (r = 0.29, P < 0.05). Salivary urea changes correlated inversely with serum phosphate (r = –0.32, P < 0.05).

Conclusion:Salivary testing shows potential to reflect some serum biochemical changes in hemodialysis patients but needs further validation before routine use.