Value of Intrarenal Artery Resistive Index for Detecting Diabetic Kidney Disease: A Cross-sectional Study

Background: The typical pattern of diabetic kidney disease (DKD) which follows glomerular hyperfiltration progressing to persistent albuminuria associated with hypertension and declining glomerular filtration rate (GFR) has changed over the years. The aim of the study is to examine the potential role of Doppler ultrasound in early identification of DKD. Methods: A 137 patients with type 1 or type 2 diabetes mellitus (DM) patients in Ethiopia participated in the study. We analyzed the correlation between resistive index (RI) of intrarenal arteries and clinical characteristics, eGFR and 24-hr urine. We evaluated the linear relationship of RI with multiple variables using multiple regression analysis. Sensitivity, specificity and area under curve (AUC) of the receiver operating curve (ROC) were assessed. Results: Among the 137 participants, 48.9% were patients with type 1 DM and 51.1% with type 2 DM. Mean age ± SD was 42±15 years. The median 24-hr urine protein was 156 (IQR=149.5) mg/24hr. Mean eGFR was 104.26±17.25 (mL/min/1.73 m 2 ). The mean RI was 0.7±0.06. The mean RI was significantly correlated with age and eGFR (r=0.64 & -0.56, P<0.001 respectively). Our multiple regression model relating mean RI to age, eGFR, systolic blood pressure (SBP), diastolic blood pressure (DBP), duration of diabetes and body mass index (BMI) was significant (overall F-test P-value<0.001). The AUC of the ROC curve of mean RI to identify a low eGFR was 0.82 (95% CI, 0.6 to 1). Sensitivity and specificity of 80% and 53% was calculated respectively. Conclusion: A significant linear relationship has been observed between RI and eGFR. This indicates RI values can determine the level of renal function loss with high accuracy.