NHR and postoperative acute kidney injury after coronary artery bypass grafting: a retrospective cohort study

Acute kidney injury (AKI) is a common and serious complication following coronary artery bypass grafting (CABG), yet reliable and easily accessible biomarkers for preoperative risk assessment remain limited. The neutrophil-to-high-density lipoprotein cholesterol ratio (NHR) is a novel indicator reflecting the balance between systemic inflammation and lipid-related protective mechanisms, but its relevance to AKI after CABG has not been fully elucidated. In this retrospective multicenter study of 1,011 patients undergoing CABG, a higher preoperative NHR was found to be independently associated with an increased risk of AKI after CABG (defined according to the KDIGO criteria within 7 days after surgery), exhibiting an approximately linear relationship. Importantly, the addition of NHR to conventional clinical risk factors improved the ability to discriminate patients at risk and enhanced risk stratification. These findings were consistent across multiple clinically relevant subgroups. Overall, preoperative NHR may serve as a simple, practical, and readily available biomarker to improve early identification of patients at high risk for AKI after CABG, supporting risk stratification and hypothesis generation for future interventional studies.