The relationship between neutrophil-to-lymphocyte ratio and acute kidney injury in pati̇ents diagnosed with acute ischemic stroke in anesthesia intensive care units 1 and 2

Stroke is the second leading cause of disability and death globally. Due to its high prevalence and significant treatment costs, it remains a concern for public health. Acute Kidney Injury (AKI), formerly known as acute renal failure, is a complex clinical condition associated with poor outcomes. It is particularly common among hospitalized patients, especially those in critical condition. AKI contributes to increased morbidity (length of hospital stay, need for renal replacement therapy) and additional mortality. The primary outcome of our study was to investigate the relationship between Neutrophil-to-Lymphocyte Ratio (NLR) and AKI in patients diagnosed with ischemic stroke and treated in the Intensive Care Unit (ICU). As a secondary outcome, we examined the relationship between NLR and mortality, length of hospital stay, and the need for renal replacement therapy (RRT). After excluding patients who did not meet the inclusion criteria, our study was conducted with the remaining 155 patients. Risk factors for AKI, including age, gender, and comorbidities (Diabetes Mellitus, Hypertension, and Coronary Artery Disease), were recorded at ICU admission. Additionally, Acute Physiology and Chronic Health Evaluation II (APACHE II) scores, Sequential Organ Failure Assessment (SOFA) scores, Simplified Acute Physiology Scores (SAPS), Urea, Creatinine, GFR, Neutrophil, Lymphocyte, NLR values, Blood Gas pH, Blood Gas Lactate values, and Blood Gas Bicarbonate values were retrospectively recorded from the Hospital Information System. In patients who developed AKI, the GFR (p<0.001) and lymphocyte (p=0.002) values at ICU admission were significantly lower than in those who did not develop AKI, while the NLR (p=0.009) and lactate (p=0.005) values were significantly higher. 30% of patients who developed AKI received renal replacement therapy, and AKI developed on average after 7,1±1,9 days. The mortality rate in patients who developed AKI (35%) was significantly higher than in those who did not (18.6%) (p<0.001). The length of stay in the ICU was also significantly longer in patients who developed AKI compared to those who did not (p<0.001). The ability of various values to predict AKI was investigated using ROC analysis, and cut-off values were determined. A cut-off value of 5.276 for NLR at ICU admission was found to have 42.5% sensitivity and 93.3% specificity, making it a good predictor. In the logistic regression analysis conducted to calculate the risk of developing AKI, the NLR value at ICU admission was found to be a risk factor for AKI according to multivariate analysis. As the NLR value increases, the risk of AKI increases, and a one-unit increase in NLR increases the risk of AKI by 1.264 (1.021-1.564) times. We found that NLR is associated with the development of AKI in patients diagnosed with ischemic stroke and that this parameter provides an important reference value for clinicians in identifying patients at risk of developing AKI. We believe that the evaluation of simple and widely accessible blood parameters, such as NLR, can contribute to planning early and targeted interventions in high-risk patient groups. Keywords: Ischemic Stroke, Acute Kidney Injury, Neutrophil-to-Lymphocyte Ratio.