Ultrasonographic imaging and Doppler analysis of renal changes in non-insulin-dependent diabetes mellitus.

Rationale And Objectives: We used ultrasonographic imaging and Doppler analysis to assess renal changes in patients with non-insulin-dependent diabetes mellitus (NIDDM) and normal renal function, as established by normal serum creatinine levels and the absence of macroalbuminuria.

Methods: Renal parenchymal echogenicity, renal volume, and resistive index (RI) were blindly evaluated for 85 NIDDM patients and 42 age-matched control subjects (C). Results were analyzed and correlated with the following clinical parameters: patient age, duration of diabetes, blood pressure, blood glucose and cholesterol levels, and the presence of microalbuminuria.

Results: Normal renal parenchymal echogenicity was seen in all but one NIDDM patient; however, in comparison with C, diabetic patients had significantly higher renal volume (mean +/- standard deviation, 314.01 +/- 72.74 vs 227.64 +/- 58.76) and RI (mean +/- standard deviation, 0.71 +/- 0.05 vs 0.64 +/- 0.02). An RI higher than 0.70 was found in 55 of 85 (65%) NIDDM patients; an increased RI was directly correlated with patient age, whereas an inverse correlation existed between an increased RI and renal volume. No statistically significant differences were observed for the duration of diabetes, arterial hypertension, blood levels of glucose and cholesterol, and the presence of microalbuminuria.

Conclusions: NIDDM patients with normal renal function show a significant increase in renal volume and RI in comparison with C. Demonstration of these findings may aid in the detection of early renal involvement in NIDDM patients. However, further investigations are needed to understand fully the correlation of such changes with the pathology of diabetic nephropathy and to provide an interpretation of the pathophysiologic mechanisms underlying changes in intrarenal vascular impedance in NIDDM patients.