Prognostic value of preoperative inflammatory and renal markers (SII, NLR, creatinine) on postoperative hospital stay and clinical outcomes in patients undergoing isolated coronary artery bypass graft surgery: a comprehensive analysis.

AIM: Coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB) induces a systemic inflammatory response, often leading to delayed recovery. This study investigated the predictive value of preoperative inflammatory markers (neutrophil-to-lymphocyte ratio [NLR], systemic immune-inflammation index [SII]) and serum creatinine on the length of hospital stay (LOS) following isolated CABG. METHODS: A single-centre, retrospective cohort study was conducted on 120 patients undergoing elective isolated CABG between January 2023 and December 2025. Patients were categorised by LOS: Group 1 (≤ 7 days, n = 88) and Group 2 (> 7 days, n = 32). Preoperative demographic, intraoperative, and laboratory data were compared. Receiver operating characteristic (ROC) and multivariate logistic regression analyses - adjusted for clinical confounders including CPB time, cross-clamp time, diabetes mellitus (DM), hypertension (HT), and number of grafts - were performed to identify predictors of prolonged stay. RESULTS: Group 2 patients were significantly older and had higher rates of male sex, DM, and HT. Operative times were also significantly longer in Group 2. Preoperative serum creatinine (1.28 ± 0.26 vs. 0.98 ± 0.19 mg/dL), NLR (3.77 ± 1.39 vs. 2.92 ± 0.96), and SII (911 ± 410 vs. 738 ± 306) were significantly elevated in the prolonged stay group (all p < 0.05). ROC analysis revealed creatinine as the strongest predictor (AUC: 0.826, cut-off > 1.1 mg/dL), followed by NLR (AUC: 0.749). In the expanded multivariate analysis adjusting for operative and clinical variables, advanced age (p < 0.001) and elevated creatinine levels (p = 0.042) remained strong independent risk factors for prolonged LOS, whereas NLR and SII did not retain independent statistical significance. CONCLUSIONS: Preoperative serum creatinine and advanced age are strong, independent predictors of prolonged hospital stay after isolated CABG. While NLR and SII are associated with longer stays, they serve better as supportive prognostic indicators in routine preoperative risk stratification.