Neutrophil-to-Lymphocyte Ratio and Platelet-to-Lymphocyte Ratio Predict Mortality in Patients with Diabetic Foot Ulcers Undergoing Amputations

Elevated platelet-to-lymphocyte ratio (PLR) and neutrophil-to-lymphocyte ratio (NLR) are associated with poor outcomes in various diseases. The objectives of this study were to explore the utility of PLR and NLR in predicting all-cause mortality in patients with diabetic foot ulcers (DFU) undergoing amputations.A retrospective observational study was performed that included a total of 348 DFU patients undergoing amputations. The primary end-point was all-cause death. According to the PLR and NLR cut-off values, patients were divided into two groups and Kaplan-Meier survival curves were constructed. Multivariable Cox regression was conducted to test the independent predictors of mortality in the study cohort.All-cause mortality was significantly higher in patients with a high PLR/NLR compared to those with a low PLR/NLR. In the low NLR group, the overall survival (OS) rates at 1, 3, and 5 years after amputation were 96.8%, 84% and 80.1%, respectively (p=0.001). In the high NLR group the corresponding OS rates at 1, 3, and 5 years were 85.2%, 58.6% and 23.9% (p<0.001). According to the multivariate analysis, age (HR 1.074, 95% CI 1.045-1.104, p<0.001), Wagner classification (HR 2.274, 95% CI 1.351-3.828, p=0.002), PLR (HR 1.794, 95% CI 1.014-3.174, p=0.045), NLR (HR 2.029, 95% CI 1.177-3.499, p=0.011), creatinine (HR 1.003, 95% CI 1.001-1.004, p<0.001) and direct bilirubin (HR 1.154, 95% CI 1.081-1.232, p<0.001) were independent predictors of mortality following amputation.Postoperative PLR and NLR values may be reliable predictive biomarkers of mortality in patients following amputation for DFU. Considering the high mortality in those patients, the patients with elevated PLR/NLR should be given more intensive in clinical practice.