Association of Renal Elasticity and Renal Function Progression in Patients with Chronic Kidney Disease Evaluated by Real-Time Ultrasound Elastography

Glomerulosclerosis and tubulointerstitial fibrosis are associated with lower renal parenchymal elasticity. This study was designed to evaluate the predictive ability of renal elasticity in patients with chronic kidney disease (CKD). 148 non-CKD patients and 227 patients with CKD were recruited. 145 (38.7%) were female, 166 (73.1%) had diabetes, the mean estimated glomerular filtration rate (eGFR) was 33.9 ± 15.8 ml/min/1.73 m2 and the median urinary protein-to-creatinine ratio (UPCR) 502 (122-1491) mg/g. Patients with later stages of CKD had lower renal elasticity values, indicating stiffer kidneys (p < 0.001), and smaller kidney (p < 0.001). Renal elasticity correlated with log-transformed UPCR (β = -7.544, P < 0.001). Renal length correlated with age (β = -0.231, P < 0.001), sex (β = -3.730, P < 0.001), serum albumin level (β = -3.024, P = 0.001), body mass index (β = 0.390, P = 0.009) and eGFR (β = 0.146, P < 0.001). In fully-adjusted logistic regression model, the odds ratio (OR) per 10 unit change in renal elasticity for rapid renal deterioration was 0.928 (95% CI, 0.864-0.997; P = 0.042). The OR per 1 mm change in renal length for rapid renal deterioration was 1.022 (95% CI, 0.994-1.050; P = 0.125). Renal elasticity is associated with proteinuria and rapid renal deterioration in patients with CKD.