Fluid Overload and Mortality in Patients with Influenza and AKI

The impact of influenza virus, particularly A(H1N1) is associated with high risk of mortality in patients who develop acute distress respiratory syndrome (ADRS). Critically ill patients with acute kidney injury (AKI) experience fluid overload; however, there are few data available on the impact of fluid overload in mortality of ADRS influenza patients. Researchers conducted a retrospective study of patients admitted to the ICU with ADRS and suspicion of influenza infection during the influenza seasons of 2016-2017 and 20170-2018.

The patients were divided into two groups: those with <10% fluid overload (group A) and those with >10% fluid overload (group B). The analysis compared mortality and incidence of AKI between the two groups.

The analysis included 40 records. Mean age was 43.5 years, 60% were male, 55% had confirmed influenza—22.7% with A(H1N1). Among the patients with A(H1N1), mortality was 100%. Twenty-four patients (60%) had AKI (12.5%, 7.5%, and 40% with Kidney Disease Improving Global Outcomes stages 1, 2, and 3, respectively). Thirteen of the AKI patients (32%) received renal replacement therapy.

AKI was diagnosed in 52% of patients in group A and 73% of patients in group B. In the entire cohort, mortality was 55%. Median fluid balance among those who survived was +3.813 mL compared with +8.370 mL among those who did not survive. Mortality in group A was 40% compared with 80% in group B (P=0.014). The odds ratio for development of AKI in group B was 2.53; odds ratio for mortality in group B was 6.0.

“In our two-year retrospective study of ARDS patients, fluid overload >10% was significantly associated with increasing incidence of AKI and mortality. A(H1N1) diagnosis involved 100% mortality,” the researchers said in their conclusion. “With these findings, we can strongly recommend a conservative fluid strategy to maintain the fluid gain in less than 10% of the initial patient’s weight. More studies with bigger cohorts are needed to clearly demonstrate these associations.”

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Source: Bonilla Li, Vera R, Ronco C, Rizo T. Fluid overload, AKI, and mortality in influenza patients: Our two-year experience. Abstract of a poster presented at the American Society of Nephrology Kidney Week 2019 (Abstract FR-PO084), November 8, 2019, Washington, DC.