Diabetic foot ulcers—comparison of performance of ankle-brachial index and transcutaneous partial oxygen pressure in predicting outcome

Diabetic foot ulcer (DFU) is the commonest condition for hospital admission and usually the starting point of most diabetic related lower limb amputations. Considering the significant role played by vascularity in the outcome of ulcer healing, we undertook this study to find out the comparative utility of commonly used vascular assessment methods. This study was a single center prospective non-randomized observational study, conducted for a period of 6 months, in diabetic patients presenting with foot ulcers of Wagner Grade II and III. The aim of our study was to compare the performances of ankle-brachial index (ABI) and transcutaneous partial pressure of oxygen (tcPO₂) measurement in predicting wound healing in diabetic ulcers and to define the optimal cut-off value for Indian patients. Five hundred sixty-four patients were included in this study, with the mean age of 58 years. Eighty-seven patients (15%) had peripheral arterial occlusive disease. Four hundred seventy ulcers (83%) healed with the mean healing days of 42.6 days. Age, duration of diabetes, serum creatinine level, and presence of infection were the factors with negative impact in wound healing. In our study, ABI value of 0.6 was found to have 100% sensitivity and 70% specificity, and tcPO₂ value of 22.5 was found to have 75% sensitivity and 100% specificity in predicting wound healing. Both ABI and tcPO₂ are complementary, but tcPO₂ is a better predictor for amputation while ABI is a better predictor for ulcer healing. While assessing the ischemic status of foot ulcer, the cut-off values should be higher in diabetics than non-diabetics.