Sonographic Features of Chronic Kidney Disease in Agricultural Community in Sri Lanka

Abstract

The aim of this study was to use ultrasound-based kidney morphological features to classify chronic kidney disease (CKD) in an agricultural community in Sri Lanka where there is a high prevalence of CKD with unknown etiology. A cohort of CKD patients (n = 50) and healthy subjects (n = 26) underwent B-mode renal ultrasound. CKD patients were further categorized as those clinically diagnosed with diabetes mellitus, hypertension, and other known causes (n = 30) and those of unknown etiology (n = 20). Following kidney morphological features were calculated: Length (LEN), width (WDTH), cortical thickness, volume (VOL), and shape index. CKD kidneys of both groups were significantly smaller than the healthy kidneys (P < 0.001). Based on a random forest procedure, the top three influential features that distinguished CKD kidneys from healthy kidneys were: VOL normalized to waist circumference (CKD = 0.6 ± 0.2 cm2, healthy = 0.9 ± 0.2 cm2), VOL normalized to body surface area (CKD = 36 ± 9 cm3/m2, healthy = 52 ± 13 cm3/m2), and WDTH (CKD = 3.6 ± 0.5 cm, healthy = 4.3 ± 0.6 cm). Patients with CKD of unknown etiology had higher kidney LEN and VOL normalized to height (HGHT) (LEN/HGHT = 0.58 ± 0.05 cm/m, VOL/HGHT = 0.40 ± 0.09 cm3/m, P < 0.05) compared to those of the known etiology group (LEN/HGHT = 0.51 ± 0.09 cm/m, VOL/HGHT = 0.30 ± 0.10 cm3/m). The study shows that ultrasound-based kidney volume can distinguish healthy versus diseased kidneys as well as CKD of known versus unknown etiology. Normalizing for height is required when comparing diseased groups.