Background: The objective of this study was to evaluate the relationship between both preoperative and postoperative Prognostic Nutritional Index values and postoperative mortality in patients undergoing Coronary Artery Bypass Grafting surgery.

Methods: This retrospective cohort study included 440 patients who underwent Coronary Artery Bypass Grafting between March 2021 and April 2023. Preoperative and postoperative Prognostic Nutritional Index values were calculated based on serum albumin concentration and peripheral blood lymphocyte count. The primary outcome was mortality, with statistical analyses performed to assess the association between Prognostic Nutritional Index values (preoperative and postoperative) and mortality using univariate and multivariate methods.

Results: A significant correlation was found between low preoperative Prognostic Nutritional Index and increased postoperative mortality risk (P < .05). A 1-unit increase in preoperative Prognostic Nutritional Index was associated with a 5% reduction in mortality risk (Odds ratio [OR] = 0.95, P < .001, 95% CI: 0.96-0.98). Similarly, the postoperative Prognostic Nutritional Index was significantly associated with mortality, with a 1-unit increase in postoperative Prognostic Nutritional Index corresponding to a 6% reduction in mortality risk (OR = 0.94, P < .001, 95% CI: 0.92-0.96). Both preoperative and postoperative Prognostic Nutritional Index values independently predicted mortality risk, with postoperative Prognostic Nutritional Index showing a stronger association with mortality outcomes.

Conclusions: The study demonstrates that both preoperative and postoperative Prognostic Nutritional Index values are critical predictors of mortality risk in Coronary Artery Bypass Grafting patients. Early assessment of the Prognostic Nutritional Index, both preoperatively and postoperatively, could enhance risk stratification and improve patient outcomes through timely interventions.