Acute kidney injury in elderly patients admitted in the intensive care unit: incidence, risk factors and mortality

• Grant number: 14/14532-7
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): November 01, 2014
• Effective date (End): November 30, 2016
• Field of knowledge: Health Sciences - Medicine - Medical Clinics
• Principal Investigator: Daniela Ponce
• Grantee: Laís Gabriela Yokota
• Host Institution: Faculdade de Medicina (FMB). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil

Abstract

Acute Kidney Injury (AKI) is defined as a sudden renal dysfunction with consequent increase of nitrogen products; which is due to the decrease of Glomerular Filtration Rate (GFR), mainly affecting the functions of filtration, excretion, hidro electrolyte and acid-base balance. AKI is a syndrome whose incidence and prevalence are higher in in-hospital population (4.9 to 7.2%), particularly in patients hospitalized in Intensive Care Units (around 40% ). Despite all therapeutic advances in the past few decades, the overall mortality of patients with AKI remains around 50%, reaching up to 80% in critical patients.Several factors may predispose a patient to AKI such as: age, sex, multiple trauma, surgery, prolonged hospital stay and comorbidities such as arterial hypertension (AH), Diabetes Mellitus (DM), heart disease, Chronic Kidney Disease (CKD), liver disease, respiratory failure and so on. The patients' age stands out, according to most studies, as an important risk factor associated with AKI because old people have a natural predisposition for the development of this syndrome as they present a high prevalence of comorbidities such as hypertension, DM, heart disease, and as they are also often admitted to the ICU. Most studies on elderly patients admitted to ICU with AKI indicate mortality rates around 60%.Due to the importance of the elderly's social role and the scarcity of studies on AKI in the elderly admitted to the ICU, more specific studies are needed.The objective of this study is to evaluate the incidence of AKI in the elderly and identify the main causes and risk factors associated with AKI in these patients. It also aims to compare the outcome of elderly patients who developed AKI with those who did not develop. A prospective observational cohort study of patients admitted to three different types of ICUs in the HC-FMB (UNESP) will be held from September 1, 2014 to September 1, 2015; daily and uninterruptedly until the patient's outcome: discharge or death. A population of 500 patients is estimated by the end of the study, included any patient aged 60 or older admitted to ICU. Patients who do not meet the definition of elderly according to Law 10.741, on October 1, 2003 as well as patients with advanced CKD (Cr Cl <30 mL / min) and renal transplanted patients are excluded from this project.For each patient, a protocol will be filled out with clinical and laboratory information obtained from the record of treatment during hospital stay. The data will be collected by the same observer, through consultation of the patient and his medical records since admission to the ICU until the outcome (discharge or death).The renal function assessment will be performed daily by the measurement of serum creatinine and urine output verification. The diagnosis of AKI will be held by the AKIN criteria. Results will be presented by descriptive statistics of the study population and different statistical tests according to the study objectives. The occurrence of AKI will then be set as dependent variable and the Chi-Square Test will be used for the statistical significance between this variable and the categorical variables while the T Test will be used for statistical significance between the dependent variable and continuous variables. After, a multivariate analysis will be performed by building a logistic regression model with calculations of Odds Ratio (OR); being all independent variables associated with the outcome included in the model, with p d 0.20. A similar procedure will be performed having the occurrence of death as the dependent variable. All results of hypothesis tests will be discussed at the 5% significance level (p <0,05).