Predicting Major Amputation Rates in Diabetic Hindfoot Ulcers With Critical Infection and Ischemia: A Risk-Factor-Based Model.

Abstract

Background: Diabetic hindfoot ulcers pose a substantially greater risk of progressing to major amputation than forefoot or midfoot ulcers. Patients with these ulcers often experience severe psychological distress at the prospect of major limb loss. Consequently, patients, their families, and healthcare professionals prioritize understanding the actual risk of major amputation based on the patient's current clinical status. However, practical tools addressing this critical and common concern remain limited. In a previous preliminary study, we proposed a model for predicting major amputation rates in diabetic hindfoot ulcers. Nonetheless, that model, which relied solely on ischemia and infection, demonstrated limited accuracy. The present study aimed to refine the prediction of major amputation in diabetic hindfoot ulcers by 1) identifying additional risk factors and 2) evaluating amputation rates according to these factors.

Methods: A retrospective analysis was conducted involving 1,663 hospitalized patients diagnosed with diabetic foot ulcers. From this group, 50 patients with hindfoot ulcers presenting with critical ischemia and infection were included. A total of 88 baseline clinical and laboratory parameters were evaluated to determine key risk factors.

Results: Chronic kidney disease (CKD) ≥ stage 3, hemoglobin < 10.35 g/dL, and albumin < 3.75 g/dL emerged as independent predictors of major amputation (P < 0.05). Univariable logistic regression demonstrated a strong positive correlation between the number of identified risk factors and the rate of major amputation. Patients without these three risk factors did not undergo major amputation, even in the presence of critical infection and ischemia. Conversely, amputation risk increased to 6% for individuals with one risk factor, 27% for those with two, and 67% for patients with all three (P < 0.001).

Conclusion: CKD, low serum hemoglobin, and low serum albumin were identified as significant risk factors for major amputation in patients with diabetic hindfoot ulcers complicated by critical infection and ischemia. The risk of major amputation increases substantially with the presence of multiple risk factors, from 6% amputation rate with one factor to 67% with three factors. Nevertheless, prospective studies with larger sample sizes are warranted to validate this risk-factor model.