Impact of Various HbA1c Levels on Short-Term Outcomes after Coronary Artery Bypass Grafting

All articles of this category (opens in new window) Background: This study evaluated the impact of preoperative glycemic status, categorized by HbA1c levels, on short-term outcomes following isolated coronary artery bypass grafting (CABG), specifically the possibility of a similar effect of Prediabetes and Diabetes on short-term outcomes and 30-day mortality. Methods: We retrospectively analyzed 3,844 patients classified based on HbA1c: A-Normoglycemia (<5.7%, n = 1,591), B-Prediabetes (5.7–6.4%, n = 1,242), and C-Diabetes (≥6.5%, n = 1,011). Baseline characteristics were compared using ANOVA and Chi-square tests. Multivariate logistic regression models were used to assess the association of HbA1c group with binary postoperative outcomes, including adjusted 30-day mortality, acute kidney injury, and stroke. Results: Prediabetic and diabetic patients were older, had lower LVEF, higher creatinine, and more hypertension compared with normoglycemia (all p < 0.01). Completeness of revascularization was lower in diabetes (70.9% vs. 76.4%, p = 0.018). Postoperative differences were found for ventilation time ( p = 0.005), major stroke (1.0% vs. 1.0% vs. 2.1%, p = 0.030), prolonged catecholamine dependency (3.0% vs. 2.3% vs. 4.6%, p = 0.008), wound infections (2.8% vs. 3.4% vs. 5.8%, p < 0.001), and 30-day mortality (1.1% vs. 0.8% vs. 2.3%, p = 0.007). In multivariable logistic regression analysis, group B and C showed a higher odds ratio (OR) of 0.65 (95% CI: 0.27–1.14; p = 0.273) and 1.72 (95% CI: 0.91–3.25; p = 0.094) for 30-day mortality, (OR) of 0.89 (95% CI: 0.42–1.90; p = 0.768) and OR of 1.77 (95% CI: 0.85–3.70; p = 0.129) for major stroke, and (OR) of 1.34 (95% CI: 0.58–3.11; p = 0.493) and OR of 1.82 (95% CI: 0.49–6.68; p = 0.370) for renal failure when compared to the reference group A. Conclusion: In patients undergoing isolated CABG, prediabetes was not associated with an increased risk of adverse short-term outcomes and higher 30-day mortality compared with normoglycemic individuals. There was a trend regarding the incidence of diabetes and higher postoperative morbidity and mortality, although this did not reach statistical significance after multivariable adjustment. These results indicate that prediabetes alone does not impose the same perioperative risk as diabetes in the context of CABG. However, the adverse trends observed in diabetic patients highlight the need for optimized perioperative management in this high-risk population. Publication History Article published online: 17 February 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany