Impact of fluid balance on mortality in patients hospitalized with COVID-19 and severe acute kidney injury

• Grant number: 23/03690-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: June 01, 2023
• End date: May 31, 2024
• Field of knowledge: Health Sciences - Medicine - Medical Clinics
• Principal Investigator: Daniela Ponce
• Grantee: Marcela Polo Costa Mafra
• Host Institution: Faculdade de Medicina (FMB). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil

Abstract

Introduction: Fluid balance (FB) was a factor identified in several studies as an independent variable for mortality in patients with Acute Kidney Injury (AKI) in an intensive care unit (ICU). Currently there are no studies that evaluate the relationship between fluid overload and mortality in patients with severe COVID-19 and AKI. Objectives: To investigate the association between FB and mortality in patients with COVID 19 and severe AKI admitted to ICUs at HC-FMB. Patients and Methods: This will be a retrospective observational cohort study. Patients admitted with a diagnosis of COVID-19 and who developed severe AKI (KDIGO 3) in the HC-FMB ICUs from April 1, 2020 to June 1, 2021 will be included in this study. Patients who do not have the diagnosis of COVID-19, severe AKI and hospitalized in other locations of the HC-FMB other than the ICU will be excluded from this project. Demographic, clinical and laboratory data is collected during hospitalization. Renal function assessment is measured by serum creatinine and by checking urinary output through consulting the patient's routine laboratory tests, calculated daily for 3 days before and 3 days after AKI diagnosis. The AKI diagnosis will be according to the KDIGO 2012 criteria. The FB in this study is calculated by subtracting the patient's fluid losses from fluid gains. These gains compose diet and intravenous or oral administration of medications or solutions. The losses are the sum of urinary output and fluid output in catheters. Insensible losses will not be considered (estimated fluid loss by mechanical ventilation, by fever and by tachypnea). The outcomes of mechanical ventilation (MV) time, length of stay in the ICU and death will be evaluated. The occurrence of death and the cumulative FB before and after the AKI diagnosis will then be established as dependent variables. The Chi-Square Test will be used to compare categorical variables and Student's t test or Mann Whitney test to compare continuous variables, according to the distribution of normality. Afterwards, multivariate analysis will be performed, through the construction of a logistic regression model, with calculations of the Odds Ratio (OR), including in the model all the variables that showed association with the outcome, with pd0.20. At the end of the study, Kaplan Meyer curves of the patients during the follow-up period will be presented.