Acute Kidney Injury Following Pediatric Liver Transplantation: A Single‐Center Retrospective Cohort Study

BACKGROUND: Acute kidney injury (AKI) is a common and serious complication following pediatric liver transplantation, but the optimal diagnostic approach and modifiable risk factors in this population remain incompletely understood. AIMS: To determine the incidence and independent risk factors of AKI following pediatric liver transplantation, and to evaluate the diagnostic performance of different Kidney Disease: Improving Global Outcomes criteria components. METHODS: Clinical data from 336 pediatric liver transplant recipients at Beijing Friendship Hospital between 2016 and 2021 were retrospectively analyzed. AKI was diagnosed and staged according to the Kidney Disease: Improving Global Outcomes criteria. Logistic regression identified independent risk factors for AKI, and clinical outcomes were compared across different AKI stages. RESULTS: AKI incidence within 7 days post-transplant was 56.0% (188/336). Creatinine criteria identified 85 cases (25.3%) of AKI, whereas urine output criteria identified 154 cases (45.8%); agreement was poor (weighted κ = 0.160). Time-to-event analysis showed creatinine criteria captured immediate postoperative renal stress, whereas urine output criteria identified evolving renal dysfunction. Multivariate logistic regression revealed that Pediatric End-Stage Liver Disease (PELD) score (OR = 1.02, 95% CI: 1.01-1.04, p = 0.009) and total intraoperative fluid volume (OR = 1.01, 95% CI: 1.01-1.01, p = 0.033) were independent predictors of AKI. Stage 1 and 2 AKI prolonged intensive care unit stay by 31.2% (p = 0.0054) and 47.0% (p = 0.0007), respectively. Overall 28-day mortality was 0.60%, and 3-year mortality was 4.17%, with no significant differences across AKI stages (p = 0.285). CONCLUSIONS: The incidence of AKI following pediatric liver transplantation is high, with urine output criteria demonstrating substantial value in capturing evolving renal dysfunction, complementing the immediate risk stratification provided by serum creatinine. PELD score and total intraoperative fluid volume were independently associated with AKI, though external validation is warranted. AKI was associated with prolonged intensive care unit stay but not long-term mortality. These findings provide a foundation for future intervention studies to test whether targeting these factors can reduce AKI incidence. CLINICAL IMPLICATIONS: Acute kidney injury is a common complication after pediatric liver transplantation, yet optimal diagnostic approaches and perioperative factors remain incompletely characterized. This study reveals the complementary nature of Kidney Disease: Improving Global Outcomes criteria: urine output criteria identified more AKI cases, while creatinine criteria enabled earlier detection. PELD score and total intraoperative fluid volume showed independent associations with AKI. These findings underscore the importance of applying both diagnostic criteria and highlight the need for prospective studies to clarify causal pathways and evaluate targeted prevention strategies.