Background: Diabetic nephropathy is the leading cause and contributor of end stage renal disease. Elevation of intrarenal resistance index (RI) is associated with diabetic nephropathy, but data is lacking in Chinese diabetic patients, and arbitrary cut-off values of RI were used to identify diabetic nephropathy in previous studies.
Aims: To assess the relationships between RI and diabetic nephropathy in Chinese diabetic patients, and to define the optimal cut-off RI value for detecting diabetic nephropathy with Receiver Operating Characteristics Curve (ROC) analysis.
Subjects and methods: 113 Chinese Diabetic men were recruited. All patients had RI measurement of interlobar arteries of both kidneys on ultrasound examinations. Serum creatinin (Cr), Albumin / creatinin ratio (ACR), and incidence of albuminuria of those patients were correlated.
Results: The RI correlated with ACR (r =0.38, p<0.001)) and creatinine (r =0.49, p ,0.001) on Pearson’s correlation. The RI was much higher in macroalbuminuria (0.76 +/- 0.07) than in microalbuminuria (0.68 +/- 0.08) which on the other hand was slightly higher than that in normoalbuminuria (0.64 +/- 0.05). On logistic regression with overt nephropathy (defined as macroalbuminuria) as dependent variable, RI and age were independent determinants after adjustments for BMI, diabetes duration, hypertension and dyslipidaemia. On ROC analysis, RI of > 0.74 was the optimal cut-off value for identifying overt nephropathy with sensitivity of 72% and specificity of 92%.
Conclusion: RI was increased in Chinese male patients with diabetic nephropathy, and RI > 0.74 was the optimal cut-off value for detecting overt nephropathy.