Post-Liver Transplant Kidney Dysfunction: Incidence of Acute Kidney Injury and Chronic Kidney Disease and Risk Factors Related to Chronic Kidney Disease Development

<b>Introduction:</b> Acute kidney injury (AKI) and chronic kidney disease (CKD) are common complications following liver transplantation (LT), significantly impacting graft and patient survival. AKI affects more than 50% of LT recipients, with a subset requiring renal replacement therapy (RRT), while CKD develops in up to 60% of cases, increasing long-term morbidity and mortality. This study aimed to determine the incidence of AKI and CKD post-LT and to identify risk factors associated with CKD development. <b>Methods:</b> All adult cirrhotic patients without concurrent CKD submitted to LT between January 2001 and December 2017 at the main transplant center in Salvador, Bahia, Brazil, with more than 6-month survival were included in the study. AKI was defined by KDIGO criteria within the first 7 days post-LT. CKD was diagnosed in the presence of the estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m² and/or proteinuria ≥ 200 mg/g 1 and 5 years after LT. Clinical and biochemical parameters were analyzed using multivariate logistic regression to identify independent predictors of CKD. <b>Results:</b> A total of 177 LT recipients (72.9% male; mean age 53.6 ± 12.6 years) were studied. AKI occurred in 51.4% of them in the first 7 days after LT, and 10 (11%) required RRT. CKD was diagnosed in 30% of LT recipients at 1 year and in 42.9% at 5 years. The majority displayed CKD stage G3 (72.4% at 5 years). Multivariate analysis identified pre-LT serum creatinine (OR 7.74, 95% CI 1.99-30.02) and AKI within 7 days after LT (OR 2.72, 95% CI 1.22-6.06) as independent predictors of CKD development. <b>Conclusions:</b> AKI is highly prevalent in the early post-LT period and is a major determinant of CKD progression. Pre-LT renal function and perioperative AKI were significantly associated with worse long-term nephrological outcomes. Optimized perioperative management and renal monitoring strategies are crucial to minimize progression to end-stage kidney disease in LT recipients.