MO298: Predictors of Renal Function Recovery in Critically ill Patients With Acute Kidney Injury
Authors: Knezevic Violeta , Azasevac Tijana , Petrovic Lada 
Published: May 2022

Abstract

BACKGROUND AND AIMS
Acute kidney injury (AKI) is a frequent and serious complication in critically ill patients admitted in intensive care unit (ICU). The development of acute kidney damage is associated with various adverse outcomes, such as prolonged stay in the ICU, the development of chronic kidney disease (CKD), increased mortality and increased treatment costs. The aim of this study was to determine the predictors of renal function recovery in critically ill patients with AKI who were treated with continuous renal replacement therapy (CRRT).

METHOD
We performed a single-centre retrospective study of 440 adult surgical and non-surgical patients with AKI or AKI episode in CKD who were admitted to the ICU between 2014 and 2018 and treated with CRRT. Demographic, clinical and laboratory parameters [urea, creatinine, C-reactive protein (CRP), procalcitonin (PCT), quick sequential organ failure assessment (qSOFA) score], comorbidities, the need for vasopressor therapy and mechanical lung ventilation on the day of confirmed AKI, as well as CRRT modalities were analysed. Renal recovery was defined by renal replacement therapy discontinuation within 90 days of its start. Patients with the Kidney Disease Improving Global Outcomes (KDIGO) stage 2 AKI and/or volume overload have had an ‘early’ start of CRRT within 24 h of the AKI diagnosis; patients with poor response to conservative treatment or evidence of clinical complications associated with AKI have had a ‘late’ start of CRRT. The patients were divided into two groups: patients with recovered renal function (RRF group) and patients who had not recovered renal function (NRRF group).

RESULTS
Out of a total of 440 patients, 242 (55%) recovered renal function. RRF versus NRRF group did not differ significantly by gender (males: 64.5% versus 69.7%) and age (mean age of 60.93 years versus 64.5 years). Cardiovascular diseases were the most common comorbidity in both groups of patients, and CKD was significantly more prevalent in the NRRF groups (88 versus 352, P &lt; .001). There were no significant differences in examined laboratory parameters in the RRF and NRRF group (urea 27.28 versus 26.68 mmol/L; creatinine 401.43 versus 373.7 μmol/L; CRP 144.38 versus 143.52 mg/L; PCT 23.07 versus 22.44 ng/L). No significant difference was found in relation to mechanical lung ventilation (234 in the RRF group versus 206 in the NRRF group; P = .18) and vasopressor therapy (221 in the RRF group versus 219 in the NRRF group; P = 0.94). Values of the qSOFA score were significantly lower (P &lt; .001) in patients with recovered renal function (Fig. 1). In the RRF group, the most commonly used CRRT modality was CVVHD (165; 37.6%), while in the NRRF group it was CVVHDF (181; 40.9%). Predictors of renal recovery in critically ill patients who were treated with CRRT were: age &lt;65 years (P = .044), an ‘early’ start of RRT (P = .043), absence of mechanical ventilation (P = .044) and absence of earlier CKD (P = .005) (Table 1). Predictors of renal recovery in septic critically ill patients with AKI treated with CRRT were: age &lt;65 years (P = .002), the absence of diabetes mellitus (P = .023) and previous CKD (P = .045) and CRP &lt; 100 mg/L (P = .033), while in critically ill patients without sepsis, the predictor of renal function recovery was the absence of previous kidney disease (P = .035).

CONCLUSION
Previous kidney disease is the most significant factor for the prediction of renal function recovery in critically ill patients with AKI treated with CRRT. Individual consideration of potential predictors of renal recovery, as well as a timely decision to initiate continuous dialysis, will prevent complications and improve the outcome of critically ill patients with AKI.