Ankle-brachial index: a surrogate marker of microvascular complications in type 2 diabetes mellitus?

The aim of this study was to investigate the potential role of ankle-brachial index (ABI) as a marker of microvascular disease in patients with type 2 diabetes mellitus.

This study included 126 type 2 diabetic patients (64 male and 62 female) with an age of 66.6+/-5.3 years (mean+/-SD) and diabetes duration of 13.2+/-4.1 years. ABI was measured with a Doppler device. The exclusion criterion was the medial arterial calcification. Patients were also examined for microalbuminuria, retinopathy and peripheral neuropathy.

ABI was significantly lower in patients with microalbuminuria than in those without microalbuminuria (0.91+/-0.17 vs 1.05+/-0.13, P=0.004), in patients with retinopathy than in those without retinopathy (0.91+/-0.18 vs 1.06+/-0.1, P=0.005), as well as in patients with neuropathy than in those without neuropathy (0.94+/-0.17 vs 1.06+/-0.11, P=0.001). Sensitivity and specificity of ABI <0.9 were 48.8% and 87.9% respectively for microalbuminuria, 39.1% and 93% respectively for retinopathy and 47% and 90.7% respectively for neuropathy. In multiple regression analysis, significant predictor of microalbuminuria was diabetes duration (P=0.0014), significant predictor of retinopathy was diabetes duration (P=0.001), while significant predictors of neuropathy were diabetes duration (P=0.001), male sex (P=0.001) and presence of retinopathy (P=0.047).

ABI is significantly lower in patients with than in those without microvascular complications of type 2 diabetes. An ABI <0.9 has a low to modest sensitivity, but a high specificity for the diagnosis of these complications. Our results suggest a potential role for ABI as a surrogate marker of microvascular complications in type 2 diabetic patients.