Analysis of prognostic risk factors in critically ill elderly patients with sepsis-associated acute kidney injury

BACKGROUND: To investigate the risk factors influencing the prognosis of critically ill elderly patients with sepsis-associated acute kidney injury (SA-AKI). METHODS: This retrospective study analyzed data from the Medical Information Mart for Intensive Care (MIMIC) Ⅳ database collected between 2008 and 2019. A total of 3,338 elderly patients with SA-AKI were included and categorized into a survival group (n = 2,448) and a death group (n = 898) based on 28-day mortality outcomes. Least Absolute Shrinkage and Selection Operator (LASSO) regression was utilized to identify potential predictors, and multivariate Cox regression was employed to analyze independent risk factors associated with 28-day mortality in elderly patients with SA-AKI. RESULTS: The 28-day mortality rate in elderly patients with SA-AKI was 26.9%. Multivariate Cox regression analysis revealed that age ≥ 76 years (Hazard Ratio[HR] = 1.392, 95% Confidence Interval[CI] 1.212-1.598, P < 0.001), creatinine ≥ 1.5 mg/dL (HR = 1.216, 95%CI 1.037-1.427, P = 0.016), urea-to-creatinine ratio (UCR) ≥ 20 (HR = 1.668, 95%CI 1.441-1.931, P < 0.001), liver disease (HR = 1.292, 95%CI 1.059-1.575, P = 0.011), renal replacement therapy (HR = 1.476, 95%CI 1.160-1.879, P = 0.002), use of norepinephrine (HR = 1.624, 95%CI 1.390-1.896, P < 0.001), dobutamine (HR = 1.644, 95%CI 1.225-2.206, P < 0.001), dopamine (HR = 1.260, 95%CI 1.008-1.576, P = 0.042), and vasopressin (HR = 1.708, 95%CI 1.430-2.041, P < 0.001) were significant risk factors for 28-day mortality in elderly patients with SA-AKI. In contrast, epinephrine use was associated with lower mortality (HR = 0.553, 95%CI 0.417-0.734, P < 0.001). CONCLUSIONS: Elderly SA-AKI patients have a high short-term mortality. Advanced age, renal impairment, liver disease, renal replacement therapy, and the use of several vasoactive drugs were associated with poor outcomes, while the potential benefit of epinephrine requires further validation. CLINICAL TRIAL NUMBER: Not applicable.