Renal Doppler ultrasonography for predicting non-diabetic kidney disease in patients with diabetes

PURPOSE: This study was conducted to assess the role of renal Doppler ultrasonography (US) in predicting non-diabetic kidney disease (NDKD) in patients with diabetes, using histologic findings as the reference standard. METHODS: Fifty-nine consecutive patients with diabetes who underwent renal Doppler US and native kidney biopsy were included in this retrospective, single-institutional study. Based on histologic findings, patients were classified as having diabetic nephropathy (DN) or NDKD. Renal Doppler US findings, including cortical echogenicity, corticomedullary differentiation, and the resistive index (RI), were compared between DN and NDKD. A subgroup analysis according to chronic kidney disease (CKD) status was also performed. RESULTS: Cortical echogenicity and corticomedullary differentiation showed no significant differences between DN and NDKD (P=0.887 and P>0.99, respectively), whereas the RI was significantly higher in patients with DN than in those with NDKD (P=0.032). The subgroup analysis revealed a significant difference in the RI between DN and NDKD in patients with diabetes and CKD (P=0.010), but a significant difference was not found in those without CKD (P=0.713). When limited to patients with diabetes and CKD, the RI had an area under the curve value of 0.759, sensitivity of 57.1%, specificity of 81.0%, positive likelihood ratio of 3.0, and negative LR of 0.5 for predicting NDKD, using a cutoff value of ≤0.69. CONCLUSION: Renal Doppler US may be useful in predicting NDKD in patients with diabetes and CKD.