The combined impact of ankle–brachial index and transcutaneous oxygen pressure on mortality in patients with type 2 diabetes and foot ulcers

Abstract

Abstract Aims A diabetic foot ulcer (DFU) is associated with increased cardiovascular risk and mortality, independently of ulcer etiology (ischemic, neuro-ischemic or neuropathic). Ankle–brachial index (ABI) is the most commonly used test when diagnosing peripheral macrovascular disease and is a well-known marker for increased cardiovascular risk. Transcutaneous oxygen pressure (TcPO2) is considered to better evaluate microvascular function and has in previous studies shown correlations with both wound healing and survival. The aim of this study was to evaluate the combined impact of a low TcPO2 (<30 mmHg) and a pathological ABI (<0.9 or ≥1.4) on three-year mortality in patients with DFU. Methods Type 2 diabetes patients aged <90 years, with at least one DFU who underwent vascular assessment with ABI and TcPO2 were screened for participation. The primary endpoint was mortality after three years, assessed from the National Death Registry in Sweden. Results The study enrolled 235 participants with a median age of 76 years. Individuals with either an abnormally high or low ABI in combination with a low TcPO2 had the worst survival rates, with three-year mortality of 54%, compared to 42% in those with one abnormal variable (either ABI or TcPO2), and 21% in those with normal ABI and TcPO2. Conclusions Combining ABI and TcPO2 when risk stratifying DFU patients seems to provide additional predictive information, not only concerning ulcer healing and limb salvage, but also on survival.