Abiraterone-Associated Renal Damage in Patients with Advanced Prostate Cancer as a Risk Factor for Mortality and Chronic Kidney Disease

<b>Background</b>: Prostate cancer is the most frequent malignancy in men, with an incidence of 21% of all diagnosed tumors in this population in Spain. Between 10 and 20% of patients with prostate cancer develop castration-resistant prostate cancer (CRPC). Abiraterone is widely used in CRPC and metastatic prostate cancer, but data on its renal safety are limited. <b>Methods</b>: We performed a single-center, retrospective observational study including patients with advanced prostate cancer who initiated abiraterone between January 2013 and July 2024 at Hospital Clínico San Carlos (Madrid, Spain). Patients were followed until December 2024. Renal events were defined as acute kidney injury (AKI), electrolyte imbalance, new onset or worsening hypertension (HTN), and/or volume overload. Risk factors and associations with mortality were analyzed using multivariate models. <b>Results</b>: Seventy-nine patients were included (mean age 76 ± 9.5 years; 70.9% CRPC; 89.9% metastatic disease). Median follow-up was 17 months. Renal events occurred in 63.3% of patients. Independent risk factors were metastatic disease (OR 13.335; 95% CI 1.418-124.444; <i>p</i> < 0.0235) and HTN (OR 3.336; 95% CI 1.091-10.206; <i>p</i> < 0.0347). Electrolyte imbalance occurred in 36.7% of patients. AKI developed in 30.4% of patients, of whom 50% progressed to chronic kidney disease. New/worsening HTN occurred in 25.5%, and volume overload occurred in 16.5%. Abiraterone discontinuation due to renal events was rare (4%). At the end of follow-up, 18.9% of patients had died. In a multivariate Cox analysis, AKI was identified as an independent predictor of mortality [HR 3.044 (95% CI 1.001-9.260); <i>p</i> = 0.05]. <b>Conclusions</b>: Renal events are common in patients treated with abiraterone, especially in those with metastatic disease and hypertension. AKI independently predicted mortality. Close monitoring of renal function and blood pressure is essential in this population.