To examine the impact of fluid overload (FO) on major adverse kidney events (MAKE) in critically ill patients with septic acute kidney injury (AKI) requiring continuous renal replacement therapy (CRRT).

This was a retrospective cohort study of patients with septic AKI treated with CRRT between January 2015 and June 2019 in Beijing Friendship Hospital, Capital Medical University. The patients were divided into two groups based on the fluid overload (fluid overload greater than 5% and fluid overload less than or equal to 5%). The demographic characteristics of patients at CRRT initiation, creatinine baseline values, basic clinical data, comorbidities, laboratory data, ICU to CRRT time, urine volume within 24 h before CRRT initiation, and disease severity assessment, and cumulative fluid balance from admission to CRRT initiation were collected. Multivariable logistic regression analysis was used to determine the risk factors of MAKE.

A total of 223 patients were enrolled, the occurrence rate of MAKE was 71.2%. Patients with fluid overload greater than 5% were more likely to experience 28-day major adverse kidney events than those with fluid overload less than or equal to 5% (88.3% vs 60.2%, P＜0.001). Binary logistic regression adjusted for confounders showed that fluid overload greater than 5% was found to be independently associated with MAKE.

In critically ill patients with septic AKI requiring continuous renal replacement therapy, greater than 5% fluid overload is associated with higher risk of 28-day major adverse kidney events, including mortality and decreased renal recovery.