Preoperative red cell distribution width to lymphocyte ratio as biomarkers for prolonged intensive care unit stay among older patients undergoing cardiac surgery: a retrospective longitudinal study

Introduction: Our aim was to use the red cell distribution width-lymphocyte ratio (RLR) as a novel biomarker to predict prolonged intensive-care unit (ICU) length of stay (LOS) among older patients undergoing cardiovascular surgery. Methods: This longitudinal study included older patients admitted to a tertiary cardiovascular surgery hospital between January 2017 and January 2022. Results: A total of 574 patients were studied, including 83 patients (14.5%) who had prolonged ICU LOS and 471 (85.5%) control subjects. After adjustment for the European System for Cardiac Operative Risk Evaluation 2, the RLR score showed a 10% increased risk of prolonged ICU LOS (odds ratio: 1.10; CI: 1.05-1.16; p = 0.01). Conclusion: Preoperative RLR can be used to predict the risk of long-term intensive care stay in older cardiac surgery patients.