Toe-brachial index is associated more strongly with albuminuria or glomerular filtration rate than ankle-brachial index in patients with type 2 diabetes.

The aim of this study was to investigate whether toe-brachial index (TBI) is more strongly associated with albuminuria or estimated glomerular filtration rate (eGFR) than ankle-brachial index (ABI), and thus is a more suitable tool for evaluating the association between peripheral artery disease (PAD) and diabetic nephropathy than ABI in patients with type 2 diabetes. We evaluated the relationships between ABI or TBI and the degree of urinary albumin excretion or eGFR, as well as the major cardiovascular risk factors, in 390 patients with type 2 diabetes. Furthermore, we compared the area under the receiver-operator characteristic curve (AUC) of TBI or ABI for albuminuria or chronic kidney disease (CKD). Low-density lipoprotein cholesterol was negatively associated with ABI. Age and duration of diabetes were negatively associated with TBI, and diastolic blood pressure and high-density lipoprotein cholesterol were positively associated with TBI. Log (urinary albumin excretion) was associated more strongly with TBI (r=-0.265, P<0.0001) than with ABI (r=-0.132, P=0.0111), and eGFR was positively associated with TBI (r=0.195, P=0.0002) but not with ABI (r=0.023, P=0.6571). The AUCs of TBI for albuminuria (P=0.0002) and CKD (P=0.0322) were significantly greater than those of ABI. In conclusion, TBI is associated more strongly with albuminuria and eGFR than ABI in patients with type 2 diabetes. Our study suggests that TBI may be a more suitable tool for evaluating the association between PAD and diabetic nephropathy than ABI in patients with type 2 diabetes.