Association between hemoglobin-to-red cell distribution width ratio and 30-day mortality after cardiac surgery.

Background: Postoperative mortality after cardiac surgery remains a significant challenge, with traditional risk scores showing limited predictive accuracy. The hemoglobin-to-red cell distribution width ratio (HRR) has emerged as a novel biomarker with potential prognostic value. This study aims to evaluate the association between preoperative HRR, red cell distribution width (RDW), and 30-day postoperative mortality in cardiac surgery patients. We hypothesized that preoperative HRR and RDW are associated with 30-day postoperative mortality in cardiac surgery patients. Methods: We conducted a retrospective study of 926 patients who underwent cardiac and aortic surgeries. Data on demographics, comorbidities, and perioperative details were extracted from electronic health records. Multivariable logistic regression was used to assess the HRR-mortality relationship, and Kaplan-Meier analysis with log-rank testing evaluated 30-day survival. Sensitivity analyses were performed to confirm robustness. Results: The 30-day mortality rate was 4.2% (38 cases). A lower HRR (≤8.73) was independently associated with increased mortality [odds ratio (OR), 0.1; 95% confidence interval (CI): 0.01-0.97; P=0.047], even after adjustment for covariates. Elevated RDW (>14.8%) also correlated with higher mortality risk, though with less robust confidence intervals. Sensitivity analyses supported the robustness of results. Kaplan-Meier survival analysis demonstrated a significantly elevated cumulative mortality rate in the low-HRR group (9.6%) compared to the high-HRR cohort (2.9%; P=0.001). Conclusions: Preoperative HRR is significantly associated with 30-day mortality in cardiac surgery patients. A low HRR (≤8.73) is an independent risk factor, suggesting its utility in risk stratification and clinical decision-making. Further studies are needed to validate these findings and explore underlying mechanisms.