Association Between Prognostic Nutritional Index and Major Amputation in Patients with Diabetic Foot Ulcers

Aim: Given the clinical importance of early risk stratification in patients with diabetic foot ulcers and the limited availability of simple and reliable biomarkers, there is a need for easily accessible parameters that can support clinical decision-making. Therefore, this study aimed to evaluate the association between the Prognostic Nutritional Index (PNI) and major amputation in patients hospitalized for diabetic foot ulcers. Methods: This retrospective observational study included patients with diabetic foot ulcers evaluated by the Diabetic Foot Board between January 2020 and August 2024, who were managed conservatively or underwent minor or major amputation. Demographic characteristics, comorbid diseases, and laboratory parameters—including C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), HbA1c, neutrophil-to-lymphocyte ratio (NLR), systemic immune-inflammation index (SII), and PNI—were compared among groups. Multivariable logistic regression analysis was performed to identify independent factors associated with major amputation, and receiver operating characteristic curve analysis was used to assess the discriminative performance of PNI. Results: The study cohort consisted of 756 cases: 216 without amputation, 338 with minor amputation, and 202 with major amputation. Significant differences were observed between the amputation and non-amputation groups with respect to age, coronary artery disease, chronic heart failure, CRP, ESR, NLR, SII, and PNI. Age, ESR, CRP, and PNI were identified as independently associated with major amputation. Conclusion: The PNI reflects both immunological and nutritional status and is independently associated with major amputation in patients with diabetic foot ulcers.