Renal Resistive Index and Estimated Glomerular Filtration Rate in Nondiabetic Chronic Kidney Disease Stage 3: A Cross-Sectional Analytical Study

Background: Renal resistive index (RRI) and estimated glomerular filtration rate (eGFR) are predictive markers for chronic kidney disease (CKD) progression. Aim: To evaluate RRI value, eGFRcr-cys and renal biomarker in nondiabetic patients with CKD stage 3 in Bangkok, Thailand. Methods: A cross-sectional analytical analysis was conducted involving nondiabetic patients with CKD stage 3, aged 35-85 years. Ultrasound was used to assess the RRI of arteries in both kidneys. Patients underwent assessments of serum and urine 24-hour. Results: Among the 61 participants (67.2% male; mean age 69.03 ± 12.59 years), the mean eGFRcr-cys was 41.63 ± 8.64 mL/min/1.73 m², and the mean RRI was 0.65 ± 0.06. Patients were categorized into three RRI groups: low (<0.65, n=35), intermediate (0.65-0.70, n=14), and high (>0.70, n=12). The high RRI group showed a mean RRI of 0.73 ± 0.05 (p < 0.01). Among those with high RRI group were significant decreased right kidney size (p<0.05) and they had a lower BMI, averaging 22.49 ± 3.48. An increase in PP (59.66 ± 13.84, p=0.04) was also significant in this group. The correlations coefficient of RRI value showed a significant positive correlation with age (p<0.05) and significant negative with BMI (p<0.05). In addition, eGFRcr-cys displayed a significant negative correlation with UAGT and 24hUP (p<0.05) and a significant while eGFRcr-cys positive correlation with both kidney size and urine iNOS(p<0.01). Conclusion: An increase in RRI is inversely linked to age, BMI, and PP. Lower eGFR is correlated with factors that cause CKD progression.