Exploring saliva as a non-invasive diagnostic tool: A comparison of urea and creatinine levels with blood

Background: Chronic Kidney Disease (CKD) is characterized by the gradual deterioration of renal function spanning months or years, with hypertension and diabetes identified as the primary culprits. This condition is categorized into five distinct stages, culminating in End-Stage Renal Disease (ESRD), a fatal condition if left untreated by replacement therapies. CKD is a systemic disorder that significantly impacts salivary composition. Consequently, saliva has the potential to serve as an indicator for creatinine and urea levels in patients suffering from chronic kidney disease parameters that are traditionally monitored via blood samples.Study Objectives: The primary goal of this research is to evaluate and compare kidney function markers specifically creatinine and urea found in both the serum and saliva of patients undergoing hemodialysis for CKD against those of healthy control subjects.Subjects, Materials and Methods: The study cohort consisted of sixty participants, separated into two distinct groups. The first group included 30 patients who had been undergoing hemodialysis for chronic kidney disease for a minimum of nine months. The second group comprised 30 healthy individuals serving as controls. Saliva samples were gathered from all participants. Renal Function Tests (RFTs) were conducted using automated analysis via the Abbott Architect and Roche-Cobas C 111 analyzers.Results: The demographic analysis revealed that the majority of patients were male (63.3%) and aged over 45 years (67%). Statistical analysis showed that serum urea levels were significantly elevated in CKD patients (157.4±37.14 mg/dl) compared to the control group (34.71±5.6 mg/dl), with a p-value of less than 0.01. Similarly, salivary urea levels were markedly higher in the patient group (116.9±50.6 mg/dl) than in the controls (50.6±21.7 mg/dl). Regarding creatinine, serum levels were significantly higher in CKD patients (10.2±3.12 mg/dl) compared to controls (0.83±0.13 mg/dl), with a p-value below 0.01. Salivary creatinine also followed this trend, showing significantly higher levels in patients (1.06±1.26 mg/dl) versus controls (0.17±0.18 mg/dl).Conclusions: The study concludes that both urea and creatinine concentrations are distinctly higher in patients with chronic kidney disease compared to healthy individuals.