#903 Continuous renal replacement therapy in octogenarian and nonagenarian AKI patients: short- and long-term outcomes by age group

Abstract Background and Aims With the increasing prevalence of acute kidney injury (AKI) among elderly populations worldwide, continuous renal replacement therapy (CRRT) has become a critical intervention. However, data on the short- and long-term outcomes of patients aged ≥80 years undergoing CRRT remain scarce. This study aimed to evaluate these outcomes and identify key prognostic factors to guide clinical decision-making. Method We conducted a single-center, retrospective observational study at Saitama Medical University International Medical Center, a Japanese university hospital specializing in Heart disease, cancer, and emergency medicine. The study included patients aged ≥80 years who underwent CRRT for AKI between April 1, 2007, and June 30, 2024. Short- and long-term survival outcomes were analyzed. Results A total of 210 patients (64.8 % male) were included, with a median age of 83 years (IQR 81–86; maximum age 96). The primary causes of AKI requiring CRRT were: • Cardiac surgery: 49 cases. • Non-surgical heart disease: 82 cases. • Sepsis: 40 cases. • Acute exacerbation of chronic kidney disease or hyperkalemia: 16 cases. • Other causes: 23 cases. The median CRRT duration was 6 days (IQR 3–14). Overall in-hospital mortality was 80.0%, with dialysis dependence at discharge observed in 33.3 % of survivors (14/42 cases). Mortality rates by cause of AKI were: • Cardiac surgery: 65.3 % (32/49). • Non-surgical heart disease: 89.0 % (73/82). • Sepsis: 95.0 % (38/40). • CKD exacerbation/hyperkalemia: 31.3 % (5/16). • Other causes: 88.0 % (20/23). • A significant difference in mortality was observed among these groups (P < 0.0001). • When comparing patients aged 80–89 with those aged ≥90, in-hospital mortality was not significantly different (80.5 % vs. 70.0%; P = 0.44). However, long-term survival outcomes differed significantly. Six-month and one-year survival rates among discharged patients were 80% vs. 33.3 % (P = 0.004) and 70.6 % vs. 0 % (P = 0.002), respectively. Conclusion In patients aged ≥80 years with AKI requiring CRRT, short-term survival outcomes did not significantly differ by age group. However, long-term survival was markedly worse in patients aged ≥90 years. These findings underscore the importance of incorporating long-term survival considerations into decision-making when initiating CRRT in nonagenarian patients.