Abstract & Overview
Introduction. There is significantly increased morbidity among patients who undergo major amputation because of diabetic foot ulcers (DFU). Various risk factors contribute to this outcome with endothelial dysfunction potentially linked to poor wound healing. The Neutrophil Lymphocyte Ratio (NLR) may indicate endothelial dysfunction. Objectives. This study aimed to evaluate the accuracy and utility of NLR as a predictor of major amputation in patients admitted for DFU, whose white blood cell counts (WBCs) were elevated or normal. Major amputation is defined as amputation above the tibiotalar joint Methodology. This retrospective cohort analysis included patients admitted at East Avenue Medical Center for DFU. The primary endpoint was major amputation of the lower extremities. Data were analyzed using Receiver Operating Characteristic (ROC) analysis and logistic regression. Results. The study included 280 DFU patients, predominantly male (62.86%) with a mean age of 57.01±10.72 years. Elevated WBC was found in 176 patients (62.86%) while 104 had normal WBC (37.14%). Major amputation of the lower extremity was performed on 112 patients (40%), with 81 having elevated WBC and 31 normal WBC. The median NLR in patients with elevated WBC undergoing major amputation was 12.86 (IQR: 2.36-95) compared to 5.71 (IQR: 1.91-31.67) in those who did not, indicating NLR as an independent predictor of major amputation (Adjusted OR 1.23; 95% CI 1.14-1.34; p<0.001). ROC analysis showed an AUC of 0.8234 with an optimal cutoff of 9.33 (72.8% sensitivity, 86.3% specificity). Other predictive variables included University of Texas Stage 3D (Adjusted OR 8.20; 95% CI 2.52-26.75; p<0.001), Wagner Grade 4 (Adjusted OR 4.6; 95% CI 1.28-16.55; p=0.019), and severe infection (Adjusted OR 2.91; 95% CI 1.22-6.93; p=0.016). For patients with normal WBC, median NLR was 18 (IQR: 1.54-45.5) in those who had major amputation versus 3.13 (IQR: 1.14-12.29) in those who did not undergo major amputation. ROC analysis showed an AUC of 0.9068 with an optimal cutoff of 6.92 (87.1% sensitivity, 98.6% specificity). NLR was also an independent predictor in these subjects (Adjusted OR 1.48; 95% CI 1.14-1.92; p=0.003) alongside smoking history (Adjusted OR 9.14; 95% CI 1.26-66.56; p=0.029) and UT3D (Adjusted OR 17.38; 95% CI 2.21-136.59; p=0.007). Conclusion. Forty percent of DFU patients had major amputations. NLR independently predicted major amputation in DFU patients with both elevated and normal WBC. Keywords. Diabetes Mellitus, Diabetic Foot Ulcer, Neutrophil Lymphocyte Ratio, Amputation