Predictors of Major Amputation and Mortality in Infected Diabetic Foot Ulcers: A Retrospective Nationwide Inpatient Sample Study

Background: Diabetic foot ulcers (DFUs) affect approximately 15% of diabetic patients and are the leading cause of non-traumatic lower extremity amputations worldwide. This study examines trends in DFU management, predictors of major amputation and in-hospital mortality, and the impact of comorbidities on outcomes. Methods: Using the Nationwide Inpatient Sample (NIS) database (2016–2019), we analyzed non-elective admissions of DFU patients categorized into four treatment groups: no surgery, debridement, minor amputation, and major amputation (below-knee or above-knee). Statistical analyses identified factors associated with major amputation and mortality. Results: A significant increase in minor amputations and debridement was observed between 2016 and 2019, while the number of major amputations declined ( p < 0.001). Comorbidities varied significantly by treatment type, with dyslipidemia (49.4–51.0%), chronic kidney disease (30.1–44.2%), and hypertension (32.9–47.0%) being the most prevalent ( p < 0.001). Major amputation was associated with the highest rate of in-hospital mortality (1.00%) and the longest hospital stay (11.2 days) ( p < 0.001). Logistic regression identified sepsis (OR = 4.9, 95% CI: 4.3–5.6), stroke (OR = 3, 95% CI: 2.1–5.5), and pulmonary embolism (OR = 3.7, 95% CI: 2–6) as key predictors of major amputation, while myocardial infarction (OR = 956, 95% CI: 319–2857) and sepsis (OR = 25, 95% CI: 20–29) were the strongest predictors of mortality ( p < 0.001). Conclusions: These findings underscore the impact of comorbidities on DFU outcomes and emphasize the need for early intervention to reduce severe complications. Future research should focus on optimizing management strategies for high-risk patients to improve clinical and surgical outcomes.