Fluid Overload in Patients with AKI Requiring CRRT and Major Adverse Events

San Diego—In critically ill patients with acute kidney injury (AKI), there is an association between fluid overload and adverse outcomes. Connor W. Woodward, and colleagues recently conducted a study designed to examine the association between fluid overload and major adverse kidney events in patients with CKI requiring continuous renal replacement therapy (CRRT).

Results of the single-center retrospective study were reported during a poster session at Kidney Week 2018. The poster was titled Fluid Overload Is Associated with Major Adverse Kidney Events in Critically Ill Patients with AKI Requiring CRRT.

The study included patients in the intensive care unit (ICU) with AKI who required CRRT; patients with end-stage renal disease, kidney transplant, or baseline estimated glomerular filtration rate (eGFR) of <15 mL/min/1.73 m2 were excluded.

Fluid overload was defined as cumulative fluid balance (from hospital admission to initiation of CRRT), expressed as a percent of admission body weight. The occurrence of a major adverse kidney event was determined up to 90 days post-discharge and consisted of the composite of mortality, dependence on RRT, and failure to recover a minimum of 50% of baseline eGFR if not on RRT. The number of ventilator-free days was a secondary outcome. The researchers utilized multivariable logistic regression and linear regression models in the analysis.

The study cohort included 481 patients. The median fluid overload was 9.9%. Fluid overload of 10%, the clinical cut-off reportedly associated with adverse outcome, was found in 49.5% (n=238) of patients on the day of initiation of CRRT. Major adverse kidney event was more common in patients with fluid overload ≥10% compared with patients with fluid overload <10% (79.4% vs 71.6%; P=.047).

Following adjustment for demographic characteristics, comorbidity, acuity of illness, and time from admission to the ICU to time of initiation of CRRT, there was an independent association between fluid overload ≥10% and a major adverse kidney event (odds ratio, 1.60; 95% confidence interval, 1.02-2.52).

In addition, for each 1-day increment from ICU admission to initiation of CRRT, the adjusted odds of a major adverse kidney event increased by 3% (P=.02). There was also an association between fluid overload ≥10% with less ventilator-free days in adjusted models (P<.01).

In conclusion, the researchers said, “Fluid overload ≥10% on the day of CRRT initiation was independently associated with major adverse kidney events and less ventilator-free days in critically ill patients that suffered from AKI requiring CRRT. Fluid overload should be a clinical parameter routinely included in the evaluation of CRRT need in critically ill patients.”

Source: Woodward CW, Li Y, Lambert J, et al. Fluid overload is associated with major adverse kidney events in critically ill patients with AKI requiring CRRT. Abstract of a poster (FR-PO278) presented at the American Society of Nephrology Kidney Week 2018, October 26, 2018, San Diego, California.