Exploring the Relationship Between Serum Creatinine and Salivary Creatinine Levels in Patients With Chronic Kidney Disease in South India: A Cross-Sectional Study.

Abstract

Background In this study, researchers investigated non-invasive methods for analyzing creatinine levels by using saliva to address the need for frequent phlebotomy in chronic kidney disease (CKD) patients, which can damage their veins due to repeated blood withdrawals for creatinine level assessments. Methods This is a cross-sectional study in a tertiary healthcare setting conducted on 50 patients diagnosed with CKD. After collecting serum and salivary creatinine, we used Pearson correlation to assess the correlation between the two factors. Results The mean age of the patients was 50 years with a standard deviation of ± 15.32 years. 33 (66%) patients were males and 17 (34%) were females. Most patients were in the age group of 51 - 70 years, comprising 26 (52%) of the sample. The serum creatinine and salivary creatinine values ranged between 7.26-12.00 and 0.45-0.98, respectively. The median values were 9.72 and 0.75, respectively. There was a very weak positive linear relationship between serum and salivary creatinine levels; however, there was no significant association between them (p = 0.52). Nonetheless, a statistically significant, moderately negative linear correlation exists between serum urea and serum albumin (r = -0.36; p = 0.01). Additionally, there is a statistically significant weak negative linear correlation between serum chloride and serum urea (r = -0.3; p = 0.03). Comparing serum chloride and serum sodium reveals a statistically significant, moderately positive linear relationship (r = 0.4; p = 0.004). Serum phosphorus and serum creatinine display a statistically significant moderate positive linear relationship (r = 0.44; p = 0.001). Moreover, estimated glomerular filtration rate (eGFR) and serum creatinine exhibit a statistically significant strong negative linear correlation (r = -0.79; p < 0.001), while eGFR and serum phosphorus demonstrate a statistically significant weak negative linear correlation (r = -0.30; p = 0.03). Conclusion The study found no significant association between salivary and serum creatinine levels. Further multicentric studies on a larger population must be conducted to find the potential correlation between serum and salivary markers.