Endocrine Abstracts

Background and aims: Atherosclerosis is more prevalent among people with chronic kidney disease (CKD) than among those with normal renal function. Ankle-brachial index (ABI) and toe-brachial index (TBI) are a simple useful method for assessing peripheral atherosclerosis. The aim of our study was to investigate whether ABI or TBI were more strongly associated with progression of diabetic nephropathy such as change of urinary albumin/creatinine ratio (ACR), serum creatinine levels and estimated glomerular filtration rate (eGFR).

Materials and methods: We recruited a total of 149 type 2 diabetics: 62 men (mean age 62.4±12.1 years) and 87 women (mean age 60.3±10.9 years) with CKD (≥ stage 2) by diabetic nephropathy and followed for 1.6±1.2 years. Renal function was evaluated by serum creatinine levels, estimated eGFR (Cockcroft-Gault equation) and urinary ACR. Baseline-to-study end changes in eGFR were calculated, and yearly change of eGFR (ml/min/year) was computed. ABI and TBI measurements were performed with the subject in a supine position, and were determined as the ratio of ankle or toe systolic blood pressure to the brachial systolic blood pressure, with both determined using an automatic device.

Results: Overall, the mean age was 61.2±11.0 years, duration of diabetes 13.8±10.5 years, HbA_1C 7.9±2.2%, ACR 1,635.2±783.3 mg/gCr, and serum creatinine 1.6±1.1 mg/dL. Mean calculated GFR was 62.8±27.1 ml/min/1.73m². ABI were 1.05±0.24 (Rt.) and 1.01±0.20 (Lt.). TBI were 0.73±0.31 (Rt.) and 0.79±0.22 (Lt.). Of the study population, 39 patients (26.1%) were smokers or ex-smokers, 135 patients (90.6%) were having hypertension, and 123 patients (82.6%) were taking ACEI or ARB. Age, duration of diabetes, serum creatinine, ACR and eGFR were significantly correlated with ABI or TBI. Mean yearly change of eGFR was 7.2±10.4 ml/min per year. Yearly change in the eGFR was negatively correlated with TBI, but not with ABI. Changes of ACR or serum creatinine were not significantly correlated with ABI or TBI. By Univariate linear regression, TBI but not ABI showed a significant negative correlation with yearly change in the eGFR (r=−0.309, P<0.05).

Conclusion: This study demonstrated that TBI may be predictor of progression of diabetic nephropathy in patients with type 2 diabetes. We suggest that toe-brachial index may help to manage appropriately as early predictors on progression of diabetic nephropathy.