Association of Acute Kidney Injury Etiology with Renal Recovery and Major Adverse Kidney Events: A Real-World Cohort Study

Background Acute kidney injury (AKI) is associated with substantial post-hospital renal and survival burden, yet large real-world cohorts linking etiology with post-discharge outcomes remain limited. Methods This single-center retrospective cohort study included 1,011 adults with AKI identified in the emergency department and followed up to 5 years. Outcomes included renal recovery, 1-year adverse kidney outcome, major adverse kidney events within 365 days (MAKE365), and post-discharge survival. Multivariable logistic and Cox regression analyses evaluated outcome-associated factors. Results Prerenal AKI was the most common etiology (59.0%), followed by renal AKI (30.5%) and postrenal AKI (10.6%). Among hospital survivors, renal AKI had the lowest renal recovery rate (67.1%) and the highest 1-year adverse kidney outcome rate (34.1%); in the overall cohort, MAKE365 was also most frequent in renal AKI (50.0%). In multivariable analysis, renal AKI remained independently associated with lack of renal recovery (aOR 4.58, 95% CI 2.92–7.17), 1-year adverse kidney outcome (aOR 4.28, 95% CI 2.78–6.58), and MAKE365 (aOR 2.63, 95% CI 1.90–3.65). Postrenal AKI was also associated with 1-year adverse kidney outcome (aOR 2.06, 95% CI 1.15–3.70). Higher AKI stage, impaired baseline or discharge kidney function, lower albumin, heart failure, dementia, and positive blood culture were also associated with adverse outcomes. Conclusion AKI etiology was associated with distinct renal and survival patterns after hospitalization. Renal AKI identified the highest-risk group for impaired renal recovery and early adverse kidney outcomes, while mortality after discharge was more closely related to age, comorbidity burden, infection, nutritional status, and residual kidney function. Etiology combined with clinical markers may guide post-AKI risk stratification and follow-up.