Background: Postoperative acute kidney injury (AKI) is a frequent and serious complication following coronary artery bypass grafting (CABG), with significant implications for patient outcomes. The uric acid to high-density lipoprotein cholesterol (UA/HDL) ratio has recently emerged as a potential marker of oxidative and metabolic imbalance. However, its role in predicting AKI after cardiac surgery remains inadequately studied.

Methods: In this prospective observational study, 300 adult patients undergoing elective on-pump CABG at SLN Medical College and Hospital, Koraput, were enrolled over a four-month period. Preoperative serum uric acid and HDL-C levels were measured, and the UA/HDL ratio was calculated. Postoperative AKI was defined according to KDIGO criteria. Comparative analysis was performed between AKI and non-AKI groups. Multivariate logistic regression was used to identify independent predictors of AKI, and receiver operating characteristic (ROC) analysis assessed the discriminative ability of the UA/HDL ratio. Subgroup analyses were conducted based on diabetes status.

Results: Postoperative AKI occurred in 42.0% of patients. The UA/HDL ratio was significantly higher in patients with AKI compared to those without (0.17 ± 0.07 vs 0.15 ± 0.04; p = 0.0003; Cohen’s d = 0.462). In multivariate logistic regression, the UA/HDL ratio was independently associated with AKI (OR = 8484.53; 95% CI: 76.25–944111.92; p = 0.0002). The UA/HDL ratio demonstrated modest discriminative performance (AUC = 0.621). Subgroup analysis showed that the association was significant in non-diabetic patients (p < 0.001), but not in those with diabetes (p = 0.317).

Conclusion: An elevated UA/HDL ratio is independently associated with an increased risk of postoperative AKI in patients undergoing elective CABG. Despite modest overall predictive performance, its ease of measurement and clinical relevance suggest that the UA/HDL ratio may serve as a useful preoperative biomarker for AKI risk stratification, particularly in non-diabetic individuals. Further studies are warranted to validate its predictive utility in diverse populations.