Sonographic Renal Cortical Thickness and Echogenicity as Correlates of Estimated Glomerular Filtration Rate in Chronic Kidney Disease: A Cross-sectional Study from North-western Nigeria

Abstract

Background: Chronic kidney disease (CKD) is an increasing public health problem in Nigeria, and accessible tools for monitoring renal structural change are needed. Ultrasonography is widely available, but sonographic renal cortical thickness (RCT) and renal cortical echogenicity (RCE) have not been adequately characterised in relation to estimated glomerular filtration rate (eGFR) in north-western Nigeria. Aim: This study assessed RCT and RCE in adults with CKD and age- and sex-matched healthy controls, and examined their correlations with eGFR. Methods: This prospective cross-sectional study included 106 adults with CKD (stages 1–5) and 106 apparently healthy controls. RCT was measured sonographically as the mean of three measurements, and RCE was graded from 0 to 4. eGFR was calculated using the Cockcroft-Gault equation. Data were analysed using SPSS version 23. Group differences were assessed using the independent t-test and chi-square test, while correlation analyses examined the relationships among RCT, RCE and eGFR. Statistical significance was set at p < 0.05. Results: Mean age was comparable between CKD patients (45.4 ± 19.1 years) and controls (45.7 ± 18.7 years; p = 0.107). Mean RCT was significantly lower in CKD patients than in controls (6.64 ± 1.44 mm versus 11.19 ± 0.90 mm; p < 0.001). RCE grades were significantly higher in CKD patients, whereas most controls had grade 0 echogenicity (p < 0.001). In CKD patients, RCT correlated negatively with RCE (r = −0.725, p < 0.001). RCT showed a moderate positive correlation with eGFR (r = 0.425, p < 0.001), while RCE showed a moderate negative correlation with eGFR (r = −0.561, p < 0.001). Conclusion: RCT decreases and RCE increases as eGFR declines in CKD. These ultrasound parameters may complement eGFR in monitoring CKD, particularly where repeated laboratory testing is limited.