A high ankle-brachial index is associated with obesity and low serum 25-hydroxyvitamin D in patients with diabetes

Peripheral artery disease (PAD), when present with diabetes, is associated with significant morbidity and mortality. The spectrum of PAD in diabetes includes atherosclerosis with stenotic disease; and diffuse medial calcification with non-compliant arteries, as reflected by high ankle brachial index. The clinical characteristics of a high ABI are less well characterized than that of low ABI. The aim of this study was to determine the unique clinical phenotype of patients with diabetes who have high ankle brachial index (ABI) reading. We performed a cross sectional observational study including 360 patients. Subjects were grouped according to normal (≥ 0.8 ≤ 1.3), low (<0.8) or high ABI (>1.3) result. Subjects with high ABI were characterised by higher BMI, higher waist/height ratio (WHtR), and lower serum lower vitamin D. Although reduced renal function and neuropathy was present more frequently in those with high ABI, this was also the case in those with low ABI. Similarly to those with low ABI result, a high ABI result was associated with increased risk of diabetic foot complications including amputation. When adjusted for known risk factors for PAD, higher WHtR and lower vitamin D were significant predictors of high ABI. These results suggest an association between increased WHtR and low vitamin D with high ABI; whether there is a causal relationship requires further exploration.