Moderate and severe chronic kidney disease predict greater 5-year mortality following major lower extremity amputation

Introduction Severe Chronic Kidney Disease (CKD) predicts greater mortality after major lower extremity amputation (LEA), but it remains poorly understood whether patients with earlier stages of CKD share similar risk. Methods We assessed long-term postoperative outcomes for patients with CKD in a retrospective chart review of 565 patients who underwent atraumatic major LEA at a large tertiary referral center from 2015 to 2021. We stratified patients by renal function and compared outcomes including survival. Results Preoperative CKD diagnosis was related to many patient characteristics, co-occurred with many comorbidities, and was associated with less follow-up and survival. Kaplan-Meier and Cox Regression analyses showed significantly worse 5-year survival for major LEA patients with mild, moderate, or severe CKD compared to major LEA patients with no history of CKD at the time of amputation (P < 0.001). Severe CKD independently predicted worse mortality at 1-year (odds ratio [OR] 2.91; P = 0.003) and 5-years (OR 3.08; P < 0.001). Moderate CKD independently predicted worse 5-year mortality (OR 2.66; P = 0.029). Conclusion This study demonstrates that moderate and severe CKD predict greater long-term mortality following major LEA when controlling for numerous potential confounders. This finding raises questions about the underlying mechanism if causal and highlights an opportunity to improve outcomes with earlier recognition and optimization CKD preoperatively.