Diagnostic Accuracy of Renal Resistive Index for Detecting Diabetic Nephropathy: A Comparative Study Against Biochemical Markers

Author(s): Dr Anika Mahfuz, Dr Saieef Zaman, Dr. Kazi Shantono Saiham, Dr. Md. Immam Hossin, Dr Kamrun Nahar, Dr Md. Rasel Ahmad, Dr S M Yunus Ali

Background: Diabetic nephropathy (DN) is a prominent microvascular complication and the predominant cause of end-stage renal disease, early and precise diagnosis is critical to prevent irreversible kidney dysfunction.

Aim: To evaluate the diagnostic performance of intra-renal index RI in detecting diabetic nephropathy using sensitivity, specificity, predictive values, overall accuracy and likelihood ratios; besides comparing with biochemical markers serum creatinine, eGFR and albumin-to-creatinine ratio (ACR) as a gold standard.

Materials and Methods: This was a cross-sectional observational study, and trains were conducted in the Department of Radiology and Imaging, Sir Salimullah Medical College Hospital, Dhaka between January 2023 to December 2024. A panel of 57 men and women with stringent inclusion/exclusion criteria. This study was approved by the institutional review board, and it met the code of ethics concerning human beings as formulated by The Declaration of Helsinki. The intrarenal RI of all patients was measured by spectral Doppler ultrasound. Statistical analysis Statistical and all data were presented as a mean ± SD using SPSS software (version 26) when appropriate statistical tests of significance are applied.

Results: Among the 57 subjects (mean age 56.39 ± 8.54 years; female, 52.6%), diabetic nephropathy was noted in 82.5% and rose significantly as duration of diabetes increased to a maximum of all cases after >20 years (>100%). Increased intrarenal RI (>0.7) was detected in 78.9% of participants and significantly associated with albuminuria; 93.3% of patients with high RI also had ACR >30 mg/g. The performance measures for the RI were as follows: sensitivity, 89.36%; positive predictive value, 93.33%; overall accuracy, 85.96%; and positive LR, 2.9.

Conclusion: Measurement of intrarenal resistive index by using Doppler ultrasonography is an effective, non-invasive and economic way to predict diabetic nephropathy with greater sensitivity and positive predictive values than standard biochemical parameters and have good correlations.